Battery pack and electric apparatus using battery pack

ABSTRACT

A battery pack includes cell units in which upper and lower battery cells are connected in series, wherein an output of series-connection and an output of parallel-connection can be switched. The cell units are respectively provided with protection circuit ICs for monitoring the state of the battery cells, and only the protection circuit on the lower cell unit side is provided with a controller 350 including a microcomputer. To adjust the power consumption for the microcomputer only provided in the lower cell unit, the circuit on the upper cell unit side is provided with a current consumption control means including dummy loads. The current consumption control means is operated in conjunction with the start-up of the microcomputer in the controller so as to equalize power consumption on the upper cell unit side and the lower cell unit side.

TECHNICAL FIELD

The present disclosure relates to an electric apparatus such as a motoror lighting having a load, and a battery pack supplying power to such anelectric apparatus.

BACKGROUND ART

Electric apparatuses such as power tools are driven by battery packsusing secondary batteries such as lithium ion batteries, and thereforecordless electric apparatuses have been devised. For example, a batterypack accommodating a plurality of secondary battery cells is used inhandheld power tools in which a tip tool is driven by a motor, and themotor is driven by electric energy stored in the battery pack. Thebattery pack is configured to be attachable to and detachable from apower tool main body. When a voltage drops due to discharging, thebattery pack is detached from the power tool main body and is chargedusing an external charging device.

Cordless power tools and electric apparatuses need to maintain apredetermined operation time and to maintain a predetermined output, andtherefore higher outputs and higher voltages have been achieved asperformance of secondary batteries has improved. In addition, aselectric apparatuses using battery packs as a power source have beendeveloped, battery packs using various voltages have becomecommercialized. In general, battery packs have a fixed output voltage.However, Patent Literature 1 proposes a power source device for anelectric apparatus, in which a plurality of battery units are providedinside a housing accommodating batteries and which can select an outputin series-connection or an output in parallel-connection using aconnection means so that the device can support apparatuses usingdifferent voltages.

CITATION LIST Patent Literature [Patent Literature 1]

Japanese Patent Laid-Open No. 2014-17954

SUMMARY OF INVENTION Technical Problem

It is troublesome for a user to prepare a plurality of kinds of batterypacks when using a plurality of electric apparatuses, and therefore itis desired to realize a convenient battery pack that supports electricapparatuses using different voltages by switching the voltage.Furthermore, instead of a power source device that is separate from anelectric apparatus main body as in Patent Literature 1, it has beendesired to realize voltage switchable battery packs that can be easilymounted in electric apparatuses.

According to the present disclosure, there are provided a battery packcapable of switching an output voltage so that it can be shared betweenelectric apparatuses using different voltages, and an electric apparatususing the battery pack.

In addition, according to an aspect of the present disclosure, there isprovided a battery pack that can be mounted in an electric apparatusmain body. The battery pack can switch a connection state of a pluralityof cell units.

In addition, according to the aspect of the present disclosure, there isprovided a battery pack including a controller that can controldischarging or charging of the battery pack while monitoring the stateof the plurality of cell units.

In addition, according to the aspect of the present disclosure, there isprovided a battery pack in which discharging or charging of the batterypack can be stably controlled regardless of the connection state of theplurality of cell units.

According to another aspect of the present disclosure, there areprovided a battery pack that balances consumption currents of aplurality of cell units included in the battery pack that is switchablebetween output voltages such as a high voltage and a low voltage, and anelectric apparatus using the battery pack.

According to still another aspect of the present disclosure, there isprovided a battery pack in which a microcomputer is provided in any oneof battery cell protection circuits provided in a plurality of cellunits.

According to still another aspect of the present disclosure, there isprovided a battery pack that can efficiently draw out capability of anelectric apparatus.

According to still another aspect of the present disclosure, there isprovided a high-function battery pack.

According to still another aspect of the present disclosure, there isprovided a battery pack having a terminal structure that can befavorably fitted into a connection terminal on an electric apparatusmain body side.

Solution to Problem

The following is description of representative features of thedisclosure disclosed in this application.

A feature of the battery pack according to a first aspect of thedisclosure is as follows.

There is provided a battery pack including at least first and secondcell units as cell units in which a plurality of battery cells areconnected in series. The cell units are configured to be switchedbetween a series-connection state in which the first and second cellunits are connected to each other in series while the first cell unit isconnected to a higher voltage side than the second cell unit and aconnection state other than the series-connection state. The batterypack includes a controller that is directly or indirectly connected tothe first and second cell units and is configured to monitor a state ofthe battery cells constituting the first cell unit and a state of thebattery cells constituting the second cell unit and to be able to outputa control signal for controlling discharging of the battery pack; apower source circuit that is connected to the controller and isconfigured to be able to supply a power source voltage to thecontroller; and a casing that accommodates the first cell unit, thesecond cell unit, the controller, and the power source circuit and isconfigured to be able to connect the battery pack to an electricapparatus main body. The power source circuit is configured to beconnected to one cell unit of the first and second cell units, thecontroller is configured to be connected to the power source circuit anda negative electrode of the one cell unit, and the power source circuitis configured to generate the power source voltage from a voltage inputfrom the one cell unit and to supply the power source voltage to thecontroller.

According to the first aspect of the disclosure, it is possible toprovide a battery pack that can be mounted in an electric apparatus mainbody. The battery pack can switch a connection state of a plurality ofcell units. In addition, it is possible to provide a battery packincluding the controller that can control discharging of the batterypack while monitoring the state of the plurality of cell units.Moreover, it is possible to provide a battery pack in which dischargingof the battery pack can be stably controlled regardless of theconnection state of the plurality of cell units because a circuit forsupplying a power source voltage to the controller is closed in one cellunit.

A feature of the battery pack according to a second aspect of thedisclosure is as follows.

The battery pack includes a first protection circuit that is connectedto the first cell unit and monitors a state of the battery cellsconstituting the first cell unit and a second protection circuit that isconnected to the second cell unit and monitors a state of the batterycells constituting the second cell unit. The controller is configured tobe connected to the first and second protection circuits and isconfigured to be able to monitor the state of the battery cellsconstituting the first cell unit via the first protection circuit and tomonitor the state of the battery cells constituting the second cell unitvia the second protection circuit.

A feature of the battery pack according to a third aspect of thedisclosure is as follows.

In the battery pack, the power source circuit is configured to beconnected to the second cell unit as the one cell unit such that thepower source voltage is supplied from the second cell unit to thecontroller via the power source circuit.

A feature of the battery pack according to a fourth aspect of thedisclosure is as follows.

The battery pack has a signal terminal that is configured to be able tobe connected to the electric apparatus main body, and the control signaloutput from the controller is configured to be output to the electricapparatus main body via the signal terminal.

A feature of the battery pack according to a fifth aspect of thedisclosure is as follows.

In the battery pack, a consumption current controller is connected tothe other cell unit of the first and second cell units, and theconsumption current controller is configured to consume power havingsubstantially the same magnitude as power consumed by the controller.

A feature of the battery pack according to a sixth aspect of thedisclosure is as follows.

In the battery pack, the consumption current controller is configured toalso consume power when the controller consumes power.

A feature of the battery pack according to a seventh aspect of thedisclosure is as follows.

The battery pack has a detection unit that is connected to thecontroller, and the detection unit is configured to detect a physicalquantity related to the battery pack or the electric apparatus main bodyconnected to the battery pack and to be able to output information ofthe physical quantity to the controller.

A feature of the battery pack according to an eighth aspect of thedisclosure is as follows.

The battery pack has a first voltage detection unit as the detectionunit connecting the other cell unit of the first and second cell unitsand the controller to each other, and the first voltage detection unitis configured to output information of a voltage of the first cell unitto the controller as the physical quantity.

A feature of the battery pack according to a ninth aspect of thedisclosure is as follows.

In the battery pack, the controller is configured to control dischargingor charging of the battery pack depending on whether the battery pack isin the series-connection state or a connection state other than theseries-connection state.

A feature of the battery pack according to a tenth aspect of thedisclosure is as follows.

The battery pack has a current detection unit as the detection unit fordetecting a current flowing in at least one battery cell of theplurality of battery cells constituting the first and second cell units,and the current detection unit is configured to output information of acurrent flowing in the battery cell to the controller as the physicalquantity.

A feature of the battery pack according to an eleventh aspect of thedisclosure is as follows.

The battery pack has a temperature detection unit as the detection unitfor detecting a temperature of at least one battery cell of theplurality of battery cells constituting the first and second cell units,and the temperature detection unit is configured to output informationof the temperature of the battery cell to the controller as the physicalquantity.

A feature of the battery pack according to a twelfth aspect of thedisclosure is as follows.

The battery pack has a second voltage detection unit as the detectionunit configured to be able to be connected to a terminal of the electricapparatus main body, and the second voltage detection unit is configuredto output information of a voltage input from the terminal of theelectric apparatus main body to the controller as the physical quantity.

A feature of the battery pack according to a thirteenth aspect of thedisclosure is as follows.

In the battery pack, the controller is configured to change a conditionfor overload protection in accordance with a kind of the electricapparatus main body.

A feature of the battery pack according to a fourteenth aspect of thedisclosure is as follows.

There is provided an electric apparatus including the battery pack, andat least a first electric apparatus main body as an electric apparatusmain body that is able to be connected to the battery pack. When thebattery pack is connected to the first electric apparatus main body, thebattery pack is in a series-connection state in which the first andsecond cell units are connected to each other in series. A secondelectric apparatus main body has a parallel-connection circuitconnecting the first and second cell units to each other in parallel.When the battery pack is connected to the second electric apparatus mainbody, the battery pack is in a parallel-connection state, and when thebattery pack is not connected to the first electric apparatus main body,the battery pack is in a non-connection state in which the first andsecond cell units are electrically independent from each other.

A feature of the battery pack according to a fifteenth aspect of thedisclosure is as follows.

There is provided the battery pack including a plurality of cell unitsin which a plurality of battery cells are connected in series. The cellunits are switchable between an output of series-connection and anoutput of parallel-connection. A protection circuit that monitors astate of the battery cells is provided for every cell unit. Amicrocomputer to which signals of a plurality of protection circuits areinput such that all the battery packs are monitored is provided in theprotection circuit that is provided in the cell unit of the plurality ofcell units in a lowermost stage connected to a ground side at a time ofseries-connection. In addition, a power source circuit that generatespower for driving the microcomputer is provided, and the power sourcecircuit generates the power from an output of the cell unit in thelowermost stage that becomes close to the ground side at the time ofseries-connection. There are two cell units constituted of an upperstage cell unit (first cell unit) that is disposed on a side close to apositive electrode terminal at the time of series-connection and a lowerstage cell unit (second cell unit) that is disposed on a side close to anegative electrode terminal. When the battery pack is mounted in theelectric apparatus main body, a connection form of the upper stage cellunit and the lower stage cell unit is set to any one ofseries-connection and parallel-connection.

According to another feature of the present disclosure, the battery packhas the signal terminal for sending out a stoppage signal (dischargingstoppage signal) to the electric apparatus main body. When an output ofan abnormality is detected from any of the plurality of protectioncircuits, the microcomputer outputs a stoppage signal for stopping anoperation of a motor of the connected electric apparatus main body. Inaddition, the protection circuit connected to the upper stage cell unitis configured to serve as a battery protection IC (integrated circuit)which individually monitors voltages between terminals of the batterycells included in the upper stage cell unit, and the protection circuitconnected to the lower stage cell unit is configured to serve as abattery management IC in which a function of a protection circuit IC anda microcomputer are integrated in one chip. Here, an adjustment circuitfor balancing total power consumption of the protection circuitincluding the microcomputer in the lower stage cell unit and powerconsumption of the protection circuit in the upper stage cell unit isprovided, such that power consumption of the protection circuits becomesuniform. The adjustment circuit has a dummy load for consuming power asmuch as that consumed by the microcomputer. Here, the adjustment circuitis provided in a circuit on the upper stage cell unit side where themicrocomputer is not provided.

According to still another feature of the present disclosure, themicrocomputer has a sleep function in which power is turned off byitself when not in operation, and the adjustment circuit includes acircuit for causing the protection circuit on the upper stage cell unitside to be in a sleep state when the microcomputer is in a sleep mode.Moreover, the protection circuit has a voltage balance adjustingfunction of balancing voltages at both ends of the plurality of cells.Two sets of positive electrode terminal and negative electrode terminalare provided independently in the battery pack. The upper stage cellunit is connected to the positive electrode terminal and the negativeelectrode terminal of one set, and the lower stage cell unit isconnected to the positive electrode terminal and the negative electrodeterminal of the other set. When the battery pack is connected to ahigh-voltage electric apparatus main body, the upper stage cell unit andthe lower stage cell unit are in the series-connection state. When thebattery pack is connected to a low-voltage electric apparatus main body,the upper stage cell unit and the lower stage cell unit are in theparallel-connection state. When the battery pack is not mounted in adifferent apparatus, power lines of the upper stage cell unit and thelower stage cell unit are in a separated state.

According to still another feature of the present disclosure, thebattery pack in which an output voltage is switched by changing two cellunits between series-connection and parallel-connection, is providedwith the first protection circuit that monitors the state of the batterycells in the first cell unit on the high voltage side at the time ofseries-connection and the second protection circuit that monitors thestate of the battery cells in the second cell unit on a low voltage sideat the time of series-connection. A discharging prohibition signal or acharging prohibition signal is sent out to the connected electricapparatus main body side by monitoring the output states of the firstand second protection circuits using the microcomputer. Since power forthe microcomputer is generated from an output of the second cell unit bythe power source circuit, power can be stably generated from the cellunit on a side where a ground potential does not change even at the timeof series-connection or at the time of parallel-connection. Variouselectric apparatuses and power tools can be operated using the batterypack described above.

According to still another feature of the present disclosure, thebattery pack has the first cell unit and the second cell unit in which aplurality of cells are connected in series. An output ofseries-connection or an output of parallel-connection of the first cellunit and the second cell unit are switchable depending on a connectedelectric apparatus main body. The microcomputer that monitors the firstcell unit and the second cell unit is provided. The microcomputerdetermines whether an output of series-connection of the first cell unitand the second cell unit is supplied or an output of parallel-connectionis supplied to the connected electric apparatus main body side andchanges a condition for overload protection in accordance with adetermination result. The condition for overload protection is a limitvalue for a current flowing in the first cell unit or the second cellunit. When the microcomputer detects that the current has exceeded thelimit value, a stoppage signal for stopping an operation of the electricapparatus main body is output.

According to still another feature of the present disclosure, two setsof positive electrode terminal and negative electrode terminal areprovided independently. The first cell unit is connected to the positiveelectrode terminal and the negative electrode terminal of one set, andthe second cell unit is connected to the positive electrode terminal andthe negative electrode terminal of the other set. When the battery packis connected to a high-voltage electric apparatus main body, the firstcell unit and the second cell unit are in the series-connection state.When the battery pack is connected to a low-voltage electric apparatusmain body, the first cell unit and the second cell unit are in theparallel-connection state. The protection circuit that monitors thestate of the battery cells is provided for every cell unit. Themicrocomputer that monitors the plurality of protection circuits isprovided in the protection circuit of any cell unit of the plurality ofcell units. The microcomputer determines whether an output of thebattery pack is an output in the series-connection state or an output inthe parallel-connection state by comparing the ground potential of thepositive electrode in the first cell unit provided on a side close tothe positive electrode terminal when the first cell unit and the secondcell unit are in series-connection and the ground potential of thepositive electrode in the second cell unit. The limit value (conditionfor overload protection) for a current is switched between when thebattery pack is connected to a high-voltage electric apparatus main bodyand when the battery pack is connected to a low-voltage electricapparatus main body. It is favorable that the limit value for a currentwhen the battery pack is connected to a high-voltage electric apparatusmain body be larger than the limit value for a current when the batterypack is connected to a low-voltage electric apparatus main body. Onlythe limit value for a current when the battery pack is connected to alow-voltage electric apparatus main body may be set without setting thelimit value for a current when the battery pack is connected to ahigh-voltage electric apparatus main body.

According to still another feature of the present disclosure, thebattery pack has an LD terminal (abnormality signal terminal) foroutputting a discharging stoppage signal output from the microcomputer.A semiconductor switching element is provided between the LD terminaland the ground. When a discharging stoppage signal is emitted from themicrocomputer, the LD terminal is subjected to grounding by inputtingthe discharging stoppage signal of the microcomputer to a gate signal ofthe semiconductor switching element. When the battery pack is notmounted in a different apparatus, the power lines of the first cell unitand the second cell unit are in an electrically separated state. Inaddition, the condition for overload protection includes any one of orboth an allowable upper limit temperature of the first cell unit and thesecond cell unit and an upper limit voltage value at the time ofcharging. When the microcomputer detects that the value has exceeded theupper limit value, a discharging stoppage signal for stopping anoperation of the electric apparatus main body is output.

According to still another feature of the present disclosure, theprotection circuit that monitors the state of the battery cells isprovided in each of an upper level cell unit and a lower level cellunit. The microcomputer is provided in the protection circuit on thelower level cell unit side positioned on the ground side at the time ofseries-connection. The microcomputer determines whether an output in theseries-connection state is supplied or an output in theparallel-connection state is supplied to the electric apparatus mainbody side by also inputting a signal of the protection circuit on theupper level cell unit side and comparing the potential of the positiveelectrode in the upper level cell unit and the potential of the positiveelectrode in the lower level cell unit and changes the condition foroverload protection in accordance with a determination result.

Advantageous Effects of Invention

According to the present disclosure, it is possible to provide thebattery pack that can be mounted in the electric apparatus main body.The battery pack can switch the connection state of the plurality ofcell units. In addition, it is possible to provide the battery packincluding the controller that can control discharging or charging of thebattery pack while monitoring the state of the plurality of cell units.Moreover, it is possible to provide the battery pack in whichdischarging or charging of the battery pack can be stably controlledregardless of the connection state of the plurality of cell units.

In addition, since an appropriate output voltage can be automaticallyobtained by only mounting the battery pack in the electric apparatusmain body without depending on a mechanical switching mechanism forswitching the output voltage, the battery pack can be shared betweenelectric apparatuses using different voltages.

In addition, since the protection circuit that monitors the state of thebattery cells is provided for every cell unit, the balance of aconsumption current can be adjusted for every battery cell.

Moreover, since the adjustment circuit for balancing the total powerconsumption of the protection circuit including the microcomputer in thelower stage cell unit and power consumption of the protection circuit inthe upper stage cell unit is provided on the upper stage cell unit side,deterioration in voltage balance between the cell units can besuppressed.

In addition, since the condition for overload protection can be changedin accordance with the kind of the electric apparatus main body, it ispossible to realize the battery pack in which capability of the electricapparatus can be drawn out efficiently.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a view for describing a situation of mounting a battery packaccording to the present disclosure in a power tool.

FIG. 2 is a perspective view illustrating a shape of a battery packmounting portion 10 of a power tool main body 1 in FIG. 1.

FIG. 3 is a perspective view of a battery pack 100 according to anexample of the present disclosure.

FIG. 4 is a perspective view of a state where an upper casing 110 of thebattery pack 100 in FIG. 3 is detached.

FIG. 5 is a view illustrating a shape of a single body of powerterminals (161 and 171, 162 and 172, and 167 and 177) in FIG. 4, (1) isa perspective view of the entirety, (2) is a perspective view of anupper terminal component 200, and (3) is a perspective view of a lowerterminal component 220.

FIG. 6 is a perspective view illustrating a state connecting the powerterminals to the power tool main body, (1) illustrates a state where thepower terminals are connected to a power tool main body 30 of thepresent example, and (2) illustrates a state where the power terminalsare connected to the power tool main body 1 in the related art.

FIG. 7(1) is a perspective view of a terminal portion 50 of the powertool main body 30 of the present example, and FIG. 7(2) is a viewillustrating a connection situation of the terminal portion 50 and thepower terminals of the battery pack 100.

FIG. 8(1) is a perspective view of a terminal portion 20 of the powertool main body 1 in the related art, and FIG. 8(2) is a viewillustrating a connection situation of the terminal portion 20 and thepower terminals of the battery pack 100.

FIG. 9 is a view illustrating a shape of a single body of a signalterminal component 240 in FIG. 4, (1) is a perspective view viewed fromthe front on the left side, and (2) is a perspective view viewed frombelow on the right side.

FIG. 10 is a view illustrating a situation of fixing a plurality ofsignal terminal components 240 to a circuit board 150, (1) is a viewviewed from the front, (2) is a view of the signal terminal component240 viewed from the left, and (3) is a bottom view of that in (1) viewedfrom a lower side.

FIG. 11 is a view illustrating shapes of a connection terminal group inFIG. 4 and a board cover 180 disposed around thereof, (1) is aperspective view, (2) is a front view, and (3) is an enlarged view of apart of the board cover 180 in (2).

FIG. 12 is a perspective view of the upper casing 110 in FIG. 3.

FIG. 13 is a perspective view for describing a method of applying aresin to the circuit board 150.

FIG. 14 is a view illustrating a first modification example of thepresent example, (1) is a perspective view of an upper terminalcomponent 260 and a lower terminal component 280, (2) is a left-sideview, and (3) is a front view.

FIG. 15 is a view illustrating a second modification example of thepresent example and is a perspective view illustrating the upperterminal component 260 and a lower terminal component 280A.

FIG. 16 is a perspective view illustrating an upper terminal component200A and the lower terminal component 220 according to a thirdmodification example of the present example, (1) is a view illustratinga state where these are connected to a main body side terminal of apower tool main body 30A, and (2) is a view illustrating a state wherethese are connected to the main body side terminal of the power toolmain body 1 in the related art.

FIG. 17 is a perspective views illustrating the upper terminal component200 and a lower terminal component 220A according to a fourthmodification example of the present example, (1) is a view illustratinga state where these are connected to the main body side terminal of apower tool main body 30B, and (2) is a view illustrating a state wherethese are connected to the main body side terminal of the power toolmain body 1 in the related art.

FIG. 18 is a perspective view illustrating a connection state withrespect to the terminal portion of a power tool main body according to afifth modification example of the present example.

FIG. 19 is a circuit diagram illustrating a state where the battery pack100 of the present example is connected to the power tool main body 1 inthe related art.

FIG. 20 is a circuit diagram of the battery pack 100 of the presentexample and is a view illustrating a state where the battery pack isconnected to an 18 V power tool main body 1A with a microcomputer.

FIG. 21 is a circuit diagram of the battery pack 100 of the presentexample and is a view illustrating a state where the battery pack isconnected to a 36 V power tool main body 30.

FIG. 22 is a flowchart illustrating a control procedure of the batterypack 100.

FIG. 23 is a view describing a specific circuit configuration of aresidual quantity display means 335 of the battery pack 100 and an uppervoltage detection circuit 322.

FIG. 24 is a detailed diagram of an input/output circuit with respect toa microcomputer 351 in FIG. 23.

FIG. 25 is a table showing a corresponding relationship between signallevels of input output ports IO0 to IO3 and a signal level of an inputport AN1 in FIG. 23.

FIG. 26 is a circuit diagram of a battery pack 100A according to asecond example of the present disclosure and is a view illustrating astate where the battery pack is connected to the power tool main body 1in the related art.

FIG. 27 is a circuit diagram of the battery pack 100A according to thesecond example of the present disclosure and is a view illustrating astate where the battery pack is connected to the 18 V power tool mainbody 1A with a microcomputer.

FIG. 28 is an exploded perspective view illustrating a battery pack 400according to a third example of the present disclosure.

FIG. 29 is an enlarged view of a part of connection terminals in FIG.28.

FIG. 30 is an enlarged view of the terminal component in FIG. 28, (1) isa perspective view, and (2) is a view for describing a contact length ina fitting portion.

FIG. 31 is a perspective view illustrating a terminal component 500according to a modification example of the third example.

DESCRIPTION OF EMBODIMENTS Example 1

Hereinafter, examples of the present disclosure will be described basedon the drawings. In the following diagrams, the same reference signs areapplied to the same parts, and description thereof will not be repeated.In this specification, as an example of an electric apparatus, a powertool that is operated by a battery pack will be described. In thedescription, a front-rear direction and a right-left direction on a mainbody side of the power tool are the directions indicated in FIG. 2, andthe front-rear direction, the right-left direction, and an up-downdirection when the battery pack is viewed in a single body are thedirections indicated in FIG. 3 based on a mounting direction of thebattery pack. For convenience of description, the mounting direction ofthe battery pack will be described as a direction based on a situationin which the battery pack side is moved without moving the power toolmain body side.

FIG. 1 is a view for describing a situation of mounting a battery packaccording to the present example in a power tool. The power tool that isa form of an electric apparatus has a battery pack, and a tip tool or aworking apparatus is driven using a rotation driving force of a motor.Various kinds of power tools have been realized, and both power toolmain bodies 1 and 30 illustrated in FIG. 1 are referred to as impacttools. The power tool main bodies 1 and 30 are tools for performingtightening work by applying a rotation force or a striking force in anaxial direction to a tip tool such as a bit or a socket wrench (notillustrated). The power tool main bodies 1 and 30 include housings 2 and32 that are outer frames forming external shapes, and handle portions 3and 33 are formed in the housing 2. Trigger-shaped operation switches 4and 34 are provided in parts of the handle portions 3 and 33, that is,near places that the index finger reaches when a worker holds the powertool main bodies 1 and 30. Battery pack mounting portions 10 and 40 formounting battery packs 15 and 100 are formed below the handle portions 3and 33.

The power tool main body 1 is an electric apparatus in the related artusing the battery pack 15 adapted to a rated voltage of 18 V. Thebattery pack 15 is a battery pack in the related art and can be mountedin the battery pack mounting portion 10 of the electric apparatus (powertool main body 1) supporting 18 V as in the combination indicated by thearrow a. Inside the battery pack 15, only one set of a cell unitconstituted of five lithium ion battery cells of a rated voltage of 3.6V connected in series is accommodated, or two sets of such cell unitsare accommodated and are connected to each other in parallel. Here, avoltage of 18 V will sometimes be referred to as a low voltage in thesense that it is a relatively low voltage. Similarly, the power toolmain body 1 or the electric apparatus main body of a rated voltage of 18V will sometimes be referred to as a low-voltage power tool main body ora low-voltage electric apparatus main body. Similarly, the battery pack15 of a nominal voltage of 18 V will sometimes be referred to as alow-voltage battery pack.

The power tool main body 30 is the electric apparatus main body of arated voltage of 36 V, and the battery pack 100 that can output 36 V asindicated by the arrow b1 is mounted in the battery pack mountingportion 40. Here, a voltage of 36 V will sometimes be referred to as ahigh voltage in the sense that it is a relatively high voltage.Similarly, the power tool main body 30 or the electric apparatus mainbody of a rated voltage of 36 V will sometimes be referred to as ahigh-voltage power tool main body or a high-voltage electric apparatusmain body. Inside the battery pack 100, two sets of cell units havingfive lithium ion battery cells of a rated voltage of 3.6 V connected inseries are accommodated, such that the battery pack 100 can be switchedbetween an output of 18 V and an output of 36 V by changing a method ofconnecting the two sets of cell units. In the present example, thebattery pack 100 is configured to support two voltages such that a lowvoltage and a high voltage can be output. Therefore, the battery pack100 can be mounted in the power tool main body 1 supporting 18 V asindicated by the arrow b2 and can also be mounted in the power tool mainbody 30 supporting 36 V as indicated by the arrow b2. Here, the batterypack 100 that can output a low voltage and a high voltage in this mannerwill sometimes be referred to as a voltage changeable battery pack. Inorder to mount the battery pack 100 in the power tool main bodies 1 and30 using different voltages as indicated by the arrows b1 and b2, it isimportant that shapes of rail portions or terminal portions of thebattery pack mounting portions 10 and 40 be substantially the sameshapes and that an output voltage of the battery pack 100 be switchable.At this time, it is important that an output voltage of the battery pack100 reliably support a rated voltage of the electric apparatus main bodyor the power tool main body to be mounted such that erroneous voltagesetting does not occur.

FIG. 2 is a perspective view illustrating a shape of the battery packmounting portion 10 of the power tool main body 1. The power tool mainbody 1 illustrated herein is an impact driver, in which a handle portionextending downward from a body part of the housing 2 is provided and thebattery pack mounting portion 10 is formed on a lower side of the handleportion. A trigger switch 4 (operation switch) is provided in the handleportion. An anvil (not illustrated) serving as an output shaft isprovided on the front side of the housing 2, and a tip tool holdingportion 8 for mounting a tip tool 9 is provided at the tip of the anvil.Here, a Phillips-head screwdriver bit is mounted as the tip tool 9. Thisis not limited to only power tools, and all electric apparatuses using abattery pack are configured to have a battery pack mounting portion 10that is formed to correspond to the shape of the battery pack to bemounted, so that a battery pack that is not suitable for the batterypack mounting portion 10 cannot be mounted. In the battery pack mountingportion 10, rail grooves 11 a and 11 b extending in parallel to thefront-rear direction are formed in inner wall parts on both right andleft sides, and a terminal portion 20 is provided therebetween. Theterminal portion 20 is manufactured through integrated molding using anon-conducting material such as a synthetic resin, and a plurality ofmetal terminals, for example, a positive electrode input terminal 22, anegative electrode input terminal 27, and an LD terminal (abnormalitysignal terminal) 28 are cast therein. In the terminal portion 20, avertical surface 20 a that constitutes an abutment surface in themounting direction (front-rear direction) and a horizontal surface 20 bare formed. The horizontal surface 20 b constitutes a surface that isadjacent to and faces an upper stage surface 115 (which will bedescribed below with reference to FIG. 3) when the battery pack 100 ismounted. A curved portion 12 that abuts a raised portion 132 (which willbe described below with reference to FIG. 3) of the battery pack 100 isformed on the front side of the horizontal surface 20 b, and aprojection portion 14 is formed near the center of the curved portion 12in the right-left direction. The projection portion 14 also serves as ascrew stopper boss of a housing of the power tool main body 1 formed tobe divided into two in the right-left direction and serves as a stopperfor limiting relative movement of the battery pack 100 in the mountingdirection.

FIG. 3 is a perspective view of the battery pack 100 according to theexample of the present disclosure. The battery pack 100 can be attachedto and detached from the battery pack mounting portions 10 and 40 (referto FIG. 1), and the battery pack 100 is automatically switched betweenoutputs of a low voltage (here, 18 V) and a high voltage (here, 36 V) inaccordance with the terminal shape on the power tool main body 1 or 30side. In order to have compatibility in attachment with a rated 18 Vbattery pack 15 (refer to FIG. 1) in the related art, the shape of themounting part of the battery pack 100 is the same as that of the batterypack 15 in the related art. A casing of the battery pack 100 is formedto include a lower casing 101 and an upper casing 110 that can bedivided in the up-down direction. The lower casing 101 and the uppercasing 110 are made of members that do not conduct electricity, forexample, a synthetic resin, and are fixed to each other using fourscrews. A mounting mechanism in which two rails 138 a and 138 b areformed to be attached to the battery pack mounting portion 10 is formedin the upper casing 110. The rails 138 a and 138 b are formed to extendin a direction parallel to the mounting direction of the battery pack100 and to protrude to right and left side surface sides of the uppercasing 110. The front side end portions of the rails 138 a and 138 bbecome open ends, and the rear side end portions become closed endsconnected to the front wall surface of the raised portion 132. The rails138 a and 138 b are formed to have shapes corresponding to the railgrooves 11 a and 11 b (refer to FIG. 2) formed in the battery packmounting portion 10 of the power tool main body 1. In a state where therails 138 a and 138 b are fitted into the rail grooves 11 a and lib, thebattery pack 100 is fixed to the power tool main body 1 or 30 by beingengaged with an engagement portion 142 a (engagement portion on theright side, not shown in FIG. 3) and an engagement portion 142 b thatconstitute claws of latches. When the battery pack 100 is detached fromthe power tool main body 1 or 30, latches 141 on both right and leftsides are pushed such that the engagement portions 142 a and 142 b moveinward and the engagement state is canceled. In this state, the batterypack 100 is moved to an opposite side in the mounting direction. Theupper casing 110 and the lower casing 101 are an example of “a casing”in the present disclosure.

A flat lower stage surface 111 is formed on the front side of the uppercasing 110, and the upper stage surface 115 formed to be higher than thelower stage surface 111 is formed near the center. The lower stagesurface 111 and the upper stage surface 115 are formed to have a steppedshape, and a connection part therebetween constitutes a stepped portion114 (vertical surface). The front side part of the upper stage surface115 from the stepped portion 114 constitutes a slot group dispositionregion 120. A plurality of slots 121 to 128 extending rearward from thestepped portion 114 on the front side are formed in the slot groupdisposition region 120. The slots 121 to 128 are cutout parts having apredetermined length in the battery pack mounting direction, and aplurality of connection terminals (which will be described below withreference to FIG. 4) that can be fitted into apparatus side terminals ofthe power tool main bodies 1 and 30 or an external charging device (notillustrated) are arranged inside the cutout parts. In the slots 121 to128, cutouts are formed not only on the upper surface parallel to themounting direction but also on the vertical surface such that theterminals on the power tool main body side can be inserted from thelower stage surface 111 side. In addition, an opening portion 113 thatopens continuously in the lateral direction is formed on the lower sideof the slots 121 to 128 and between the stepped portion 114 and thelower stage surface 111.

In the slots 121 to 128, the slot 121 on a side close to the rail 138 aon the right side of the battery pack 100 constitutes an insertion portof a charging positive electrode terminal (C-positive terminal), and theslot 122 constitutes an insertion port of a discharging positiveelectrode terminal (positive terminal). In addition, the slot 127 on aside close to the rail 138 b on the left side of the battery pack 100constitutes an insertion port of a negative electrode terminal (negativeterminal). Generally, in the battery pack 100, the positive electrodeside and the negative electrode side of the power terminal are disposedsufficiently apart from each other. When viewed from a verticalimaginary surface positioned at the center in the right-left direction,the positive electrode terminal is provided at a sufficiently farposition on the right side, and the negative electrode terminal isprovided at a sufficiently far position on the left side. A plurality ofsignal terminals for transmitting a signal to the battery pack 100, thepower tool main bodies 1 and 30, and an external charging device (notillustrated) are disposed between the positive electrode terminal andthe negative electrode terminal. Here, four slots 123 to 126 for signalterminals are provided in a power terminal group. The slot 123 is apreliminary terminal insertion port, and no terminal is provided in thepresent example. The slot 124 is an insertion port for a T terminal foroutputting a signal that becomes identification information of thebattery pack 100 to the power tool main body or the charging device. Theslot 125 is an insertion port for a V terminal for inputting a controlsignal from the external charging device (not illustrated). The slot 126is an insertion port for an LS terminal for outputting temperatureinformation of the battery obtained by a thermistor (thermosensitiveelement) (not illustrated) that is provided in contact with the cell.The slot 128 for an LD terminal outputting an abnormality stoppagesignal of a battery protection circuit (which will be described below)that is further included in the battery pack 100 is provided on the leftside of the slot 127 constituting the insertion port of the negativeelectrode terminal (negative terminal).

The raised portion 132 is formed to be raised on the rear side of theupper stage surface 115. The external shape of the raised portion 132has a shape that is raised upward from the upper stage surface 115, anda depressed stopper portion 131 is formed near the center thereof. Thestopper portion 131 constitutes an abutment surface of the projectionportion 14 (refer to FIG. 2) when the battery pack 100 is mounted in thebattery pack mounting portion 10. If the projection portion 14 on thepower tool main body 1 side is inserted until it abuts the stopperportion 131, a plurality of terminals (apparatus side terminals)arranged in the power tool main body 1 and a plurality of connectionterminals (which will be described below with reference to FIG. 4)arranged in the battery pack 100 come into contact with each other, andare thus in a conducting state. In addition, the engagement portion 142a (engagement portion on the right side, not shown in FIG. 3) and theengagement portion 142 b of the latches 141 of the battery pack 100 areejected outward in the vertical direction in lower portions of the rails138 a and 138 b due to action of a spring and are interlocked withrecessed portions (not illustrated) formed in the rail grooves 11 a and11 b of the power tool main body 1, such that the battery pack 100 isprevented from falling off. A slit 134 (cooling air inlet) connected tothe inside of the battery pack 100 is provided on the inner side of thestopper portion 131. In addition, in a state where this battery pack 100is mounted in the power tool main body 1, the slit 134 is covered in aclosed state such that it is not visible from the outside. The slit 134is a vent-hole used for causing air for cooling to forcibly flow intothe battery pack 100 when the battery pack 100 is coupled to thecharging device (not illustrated) and is charged, and cooling air takeninto the battery pack 100 is discharged to the outside through a slit104 (exhaust vent-hole) provided in a front wall of the lower casing101.

FIG. 4 is a perspective view of a state where the upper casing 110 ofthe battery pack 100 in FIG. 3 is detached. Ten battery cells areaccommodated in an internal space of the lower casing 101. Two screwholes 103 a and 103 b for screwing to the upper casing 110 are formed onthe front wall surface of the lower casing 101, and screws (notillustrated) pass through the screw holes 103 a and 103 b in apenetrating manner in the upward direction from below. Two screw holesare also formed in a rear wall surface of the lower casing 101 (notshown in this diagram). A plurality of battery cells (not illustrated)are fixed by a separator 145 in a state of being stacked in two stageswith five in each stage. The separator 145 is made of a synthetic resinand is formed such that only both right and left sides constituting bothend portions of the battery cells open. Inside the separator 145, thebattery cells are stacked such that axes thereof are parallel to eachother, and adjacent cells are disposed such that directions thereof arealternately opposite to each other. Five battery cells are connected inseries by connecting the positive electrode terminals and the negativeelectrode terminals of adjacent battery cells using metal connection tab(not illustrated). Here, an upper cell unit 146 (which will be describedbelow with reference to FIG. 6) constituted of five battery cells thatare installed in an upper stage and are connected in series is formed,and five battery cells that are installed on the lower side and areconnected in series forms a lower cell unit 147 (which will be describedbelow with reference to FIG. 6). Here, the upper side and the lower sideof the cell unit do not denote that the battery cell is in the upperstage or the lower stage inside the lower casing 101. The cell unitpositioned on the ground side when two cell units are connected inseries will be referred to as “a lower cell unit”, and the cell unitpositioned on a high voltage side when connected in series will bereferred to as “an upper cell unit”. The upper cell unit 146 is anexample of “a first cell unit” in the present disclosure, and the lowercell unit 147 is an example of “a second cell unit” in the presentdisclosure. In addition, a state where the upper cell unit 146 and thelower cell unit 147 are connected in series is an example of “aseries-connection state” in the present disclosure.

Regarding the battery cells, lithium ion battery cells (not illustrated)that have a so-called size of 18650 with a diameter of 18 mm and alength of 65 mm and can be charged and discharged a plurality of timesare used. In the present example, in order to have a switchable outputvoltage from the battery pack 100, the forms of a series-connectionvoltage (high voltage side output) and a parallel-connection voltage(low voltage side output) of the plurality of cell units can beselected. Therefore, conforming to the idea of the present example, aslong as the same number of cells are included in each of the cell units,the number of cell units is arbitrary. However, the number of cell unitsis set to be an even number, such as two or four. The battery cells tobe used are not limited to only the size of 18650, and they may bebattery cells having a so-called size of 21700 or battery cells havingother sizes. In addition, the shapes of the battery cells are notlimited to only a cylindrical shape, and they may have a rectangularparallelepiped shape, a laminated shape, and other shapes. The kind ofthe battery cells is not limited to only lithium ion batteries, andsecondary batteries of an arbitrary kind such as nickel-hydride batterycells, lithium ion polymer battery cells, and nickel-cadmium batterycells may be used. Two electrodes are provided at both ends of thebattery cell in the length direction. One of the two electrodes is apositive electrode and the other is a negative electrode. However,positions for providing the electrodes are not limited to only both endsside, and the electrodes may be arbitrarily disposed as long as a cellunit can be easily formed inside the battery pack.

A circuit board 150 is disposed on the upper side of the separator 145holding the battery cells. In the circuit board 150, a plurality ofconnection terminals (161, 162, 164 to 168, 171, 172, and 177) are fixedthrough soldering, and a circuit pattern and the connection terminalsare electrically connected to each other. Moreover, various electronicelements (not illustrated herein) such as a battery protection IC, amicrocomputer, a PTC (positive temperature coefficient) thermistor, aresistor, a capacitor, a fuse, or a light emitting diode are mounted inthe circuit board 150. The circuit board 150 is fixed such that itextends in the horizontal direction on the upper side of the separator145 that is a non-conductor formed of a synthetic resin or the like.Regarding the material of the circuit board 150, it is possible to use asingle-layer substrate, a double-sided substrate, or a multi-layersubstrate referred to as a printed board in which a pattern wiring isprinted using a conductor such as a copper foil on a substrate realizedby having a raw material impregnated with a resin having insulationproperties. In the present example, a double-sided substrate is used, sothat the circuit board 150 has the upper surface (front surface, that isa surface on the upper side as seen in FIG. 4) and the lower surface(rear surface). The plurality of connection terminals (161, 162, 164 to168, 171, 172, and 177) are disposed on the front side slightly from thecenter of the circuit board 150 in the front-rear direction. Here, theplurality of connection terminals are disposed substantially side byside in the lateral direction.

Each of the connection terminals is provided by being engraved on theupper stage surface of the upper casing 110 as illustrated in FIG. 3.Sequentially from the right side to the left side in the circuit board150, the C-positive terminals (161 and 171: charging positive electrodeterminals), the positive terminals (162 and 172: discharging positiveelectrode terminals), the T terminal 164, the V terminal 165, the LSterminal 166, the negative terminals (167 and 177: negative electrodeterminals), the LD terminal 168 are disposed side by side. Here, thepower supply line connection terminals from the battery pack, that is,the power terminals are constituted of two separated terminalcomponents. That is, the C-positive terminals (charging positiveelectrode terminals) are constituted of the upper positive electrodeterminal 161 and the lower positive electrode terminal 171, and the pairof positive electrode terminals (161 and 171) is disposed at a placecorresponding to the single slot 121. An arm portion set of the upperpositive electrode terminal 161 is disposed on the upper side of theinner part of the slot 121, and an arm portion set of the lower positiveelectrode terminal 171 is disposed on the lower side of the arm portionset of the upper positive electrode terminal 161. In a similar manner,the positive terminals (discharging positive electrode terminals)provided by being engraved on the upper casing 110 are constituted ofthe upper positive electrode terminal 162 and the lower positiveelectrode terminal 172, and the pair of positive electrode terminals(162 and 172) is disposed at a place corresponding to the single slot122. An arm portion set of the upper positive electrode terminal 162 isdisposed on the upper side of the slot 122 part, and an arm portion setof the lower positive electrode terminal 172 is disposed on the lowerside of the arm portion set of the upper positive electrode terminal162. The negative terminals (negative electrode terminals) provided bybeing engraved on the upper casing 110 are constituted of the uppernegative electrode terminal 167 and the lower negative electrodeterminal 177, and the pair of negative electrode terminals (167 and 177)is disposed at a place corresponding to the single slot 127. An armportion set of the upper negative electrode terminal 167 is disposed onthe upper side of the slot 127 part, and an arm portion set of the lowernegative electrode terminal 177 is disposed on the lower side of the armportion set of the upper negative electrode terminal 167.

The connection terminals (161, 162, and 164 to 168) are disposed atpositions corresponding to the slots 121 to 128 as illustrated in FIG.3. Therefore, the connection terminals are disposed such that fittingparts of the connection terminals open toward the upper side and thefront side from the circuit board 150. However, a part between the upperpositive electrode terminal 162 and the T terminal 164 becomes a freespace that is not used in the battery pack 100 of the present example,similar to the battery pack 1 in the related art (refer to FIG. 1).

The pair of charging positive electrode terminals (161 and 171) isconfigured to be offset to the front side beyond the pair of dischargingpositive electrode terminals (162 and 172) disposed to be adjacentthereto. The configuration is realized due to spatial restriction and inorder to avoid a movement range of a latch mechanism (not illustrated)immediately behind the pair of positive electrode terminals (161 and171). Therefore, if there is no spatial restriction, it is favorablethat the pair of positive electrode terminals (161 and 171) be disposedsuch that front end positions of the pair of positive electrodeterminals (162 and 172) and the pair of negative electrode terminals(167 and 177) are aligned.

The positive electrode terminals (161, 162, 171, and 172) and thenegative electrode terminals (167 and 177) are disposed at places faraway from each other in the right-left direction, and three signalterminals (T terminal 164, V terminal 165, and LS terminal 166) areprovided therebetween. In the present example, as a component for asignal terminal, a component provided with two sets of arm portionsextending in the horizontal direction in total including one set on theright and left on the upper side and another set on the right and lefton the lower side are used. However, the detailed shape thereof will bedescribed below with reference to FIG. 9. Regarding the signal terminals(164 to 166 and 168), a signal terminal component having one arm portionin the up-down direction used in the related art can be used without anychange. However, in the present example, in order to achieve anequivalent fitting state of the positive electrode terminals (161, 162,171, and 172) and the negative electrode terminals (167 and 177) withrespect to the apparatus side terminals, a signal terminal component(which will be described below with reference to FIG. 9) having two armportions on the upper and lower sides on the signal terminal side isused.

A signal terminal, that is, the LD terminal 168 is further provided onthe left side of the pair of negative electrode terminals (167 and 177).The LD terminal 168 is also formed to have two sets of arm portions onthe upper side and the lower side. However, the LD terminal 168 differsfrom other signal terminals (T terminal 164, V terminal 165, and LSterminal 166) in size. The configuration is realized due to spatialrestriction. Since the latch mechanism (not illustrated) reaches a placeimmediately behind the LD terminal 168, the LD terminal 168 is formed tobe smaller than other signal terminals in order to avoid the latchmechanism. Leg portions of all the signal terminals (164 to 166 and 168)penetrate the attachment hole 151 formed in the circuit board 150 fromthe front surface to the rear surface and are fixed to the rear surfaceside through soldering. The present example also has a feature in amethod of fixing three signal terminals (164 to 166), and detailsthereof will be described below with reference to FIG. 9 and FIG. 10. Asdescribed above, an electronic element (not illustrated) is mounted onthe circuit board 150, and the plurality of connection terminals arefixed through soldering. Thereafter, the circuit board 150 is fixed tothe separator 145 through screwing, bonding, or the like.

Four LEDs (not illustrated) are provided near the rear side of thecircuit board 150, and prisms 191 to 194 having a slender rectangularparallelepiped shape in the up-down direction are provided on the upperside of the LEDs. The prisms 191 to 194 are disposed to face lightingsurfaces of the LEDs (light emitting diodes, not illustrated) of whichbottom surfaces performs upward irradiation and are provided such thatobliquely-cut upper surfaces are exposed to the outside through a slit(not illustrated) formed in the upper casing 110. The prisms 191 to 194are provided to scatter light and to perform irradiation to the outsideof the upper casing 110. The four LEDs (not illustrated) are used fordisplaying the residual quantity of the battery pack 100. When a workerpushes a switch 190, as many LEDs as the number corresponding to thevoltage of the battery cell are lit only for a certain period of time(details will be described below with reference to FIG. 24 and FIG. 25).An operation lever (not illustrated) for operating the switch 190 isprovided in an outer surface part of the upper casing 110 such that itcan be operated by a worker. The lower casing 101 has a substantiallyrectangular parallelepiped shape in which the upper surface opens, andthe lower casing 101 is constituted of a bottom surface; and a frontsurface wall 101 a, a rear surface wall 101 b, a right side wall 101 c,and a left side wall 101 d extending in the vertical direction withrespect to the bottom surface. The slit 104 is provided substantially inthe center of the front surface wall 101 a. The slit 104 is used as adischarge port for discharging cooling air sent out from the chargingdevice side to the internal space of the battery pack 100 when chargingis performed by the charging device.

Next, shapes of components (200 and 220) used for the power terminalswill be described using FIG. 5. FIG. 5(1) is a perspective viewillustrating component single bodies of the upper terminal component 200and the lower terminal component 220. The upper terminal component 200is a common component used for the upper positive electrode terminals161 and 162 and the upper negative electrode terminal 167, and the lowerterminal component 220 is a common component used for the lower positiveelectrode terminals 171 and 172 and the lower negative electrodeterminal 177. The upper terminal component 200 and the lower terminalcomponent 220 are formed by press-cutting a flat plate formed of aconductive metal through pressing and bending the cut plate into aU-shape. The upper terminal component 200 is folded such that a surfaceconstituting a U-shaped bottom portion, that is, a bridge portion 202becomes the upper side. The lower terminal component 220 is folded suchthat a bridge portion 222 becomes the rear side. The bridge portions 202and 222 formed to be folded into a U-shape are disposed to intersecteach other substantially at a right angle in this manner because an areaof the side wall surface cannot be sufficiently ensured in thefront-rear direction for the bridge portion 222 on the front side, andthe bridge portion is reduced in size if the bridge portion is disposedon the upper side. In the lower terminal component 220 of the presentexample, the bridge portion 222 is provided in the vertical surfacedirection. Therefore, the length in the front-rear direction requiredfor disposition can be shortened, and the size of the bridge portion,particularly the length in the up-down direction can be sufficientlyensured, so that the rigidity of the lower terminal component 220 can beenhanced. Meanwhile, in the upper terminal component 200, long armportions 205 and 206 straddling the lower terminal component 220 can beformed, and the bridge portion 202 that constitutes a surface extendingin the same direction as the front-rear direction in which the armportions 205 and 206 extend is provided, so that the attachment rigidityof the arm portions 205 and 206 can be enhanced.

The upper terminal component 200 has a right side surface 203 and a leftside surface 204 that are formed by being folded into a U-shape to beparallel to each other, and the bridge portion 202 that constitutes theupper surface connecting those to each other. The arm portions 205 and206 are provided inward from both right and left sides on the front sideof the right side surface 203 and the left side surface 204 whilesandwiching the apparatus side terminal therebetween. A region of thefront side portion on the left side surface 204 from the lower side to aposition near the upper end is formed to extend linearly in the verticaldirection and to extend to the front side from a place near an arrow 204d close to the upper end in a manner of exhibiting a curve having asignificant radius of curvature. The shape of the right side surface 203is formed to have plane symmetry with the left side surface 204. The armportion 205 is disposed to extend to the front side from the upper frontside of the right side surface 203, and the arm portion 206 is disposedto extend to the front side from the upper front side of the left sidesurface 204. In this manner, the arm portions 205 and 206 are formed toextend to the front side from the upper side part of the front sideportion of a base body portion 201, that is, in a direction parallel tothe mounting direction of the battery pack 100. The arm portions 205 and206 face each other when viewed in the right-left direction and havespring properties through pressing such that the smallest gap parts,that is, fitting portions fitted into the apparatus connection terminalsapproach a position where they almost come into contact with each other.Here, pressing denotes plastic working performed by using a pressmachine. A raw material such as a sheet metal is pressed to a die with ahigh pressure, is subjected to shearing such as cutting, punching, anddrilling, and is further subjected to bending or drawing as necessary,and are thus sheared and formed to have a desired shape. In the presentexample, the upper terminal component 200 and the lower terminalcomponent 220 are formed of flat plates having a thickness ofapproximately 0.5 to 0.8 mm, for example. Accordingly, the positiveelectrode terminals 161, 162, 171, and 172 and the negative electrodeterminals 167 and 177 have a high mechanical strength, so that a fittingpressure when being fitted into the apparatus side terminals isenhanced. Heat treatment, plating treatment, or the like may beperformed after pressing.

The lower terminal component 220 is also manufactured in a similarmanner and has a right side surface 223 and a left side surface 224 thatare formed by being folded into a U-shape to be parallel to each other,and a base body portion 221 that constitutes the bridge portion 222connecting those to each other. The arm portions 225 and 226 are formedon the front side from places near slender upper portions on the rightside surface 223 and the left side surface 224. The arm portions 225 and226 have shapes sandwiching the apparatus side terminal therebetweeninward from both right and left sides. A distance S between the upperend position of the arm portion set (205 and 206) on the upper side andthe lower end position of the arm portion set (225 and 226) on the lowerside is configured to be substantially equivalent to the width of thepower terminal provided in the 18 V battery pack in the related art.Meanwhile, the arm portion set (205 and 206) on the upper side and thearm portion set (225 and 226) on the lower side are disposed to be awayfrom each other by a predetermined distance S1 in the up-down direction.A cutout portion 231 significantly cut out from the front side is formedbelow the arm portion set (225 and 226) on the lower side. The rear sideof the lower terminal component 220 is fixed side by side with the rightside surface 203 and the left side surface 204 of the upper terminalcomponent 200 in the front-rear direction with a predetermined clearance211 therebetween such that they do not come into contact with eachother.

FIG. 5(2) is a perspective view of a single body of the upper terminalcomponent 200. Here, the region of the bridge portion 202 and parts ofleg portions 207 and 208 are illustrated by applying hatching thereto,such that the area thereof becomes clear. In this specification, thebase body portion 201 indicates a part exposed to the upper side fromthe front surface of the circuit board 150 to be attached, that is, apart excluding the arm portions 205 and 206. The base body portion 201of the upper terminal component 200 is constituted of the right sidesurface 203, the left side surface 204, and the bridge portion 202. Theleg portions 207 and 208 are connected to parts below the lower sideportion of the base body portion 201. The leg portions 207 and 208 areinserted into the attachment hole (penetration hole) of the circuitboard 150. The leg portions 207 and 208 protrude from an attachmentsurface (front surface) of the circuit board 150 to a surface on a sideopposite to an attachment surface (rear surface), the leg portions 207and 208 are soldered to the circuit board 150 on the rear surface. Inaddition, through soldering, the arm portions 205 and 206 areelectrically connected to the battery cells, the electronic element, andthe like mounted on the circuit board 150. Here, the leg portions 207and 208 are formed to have a height H1 greater than the thickness of thecircuit board 150 to an extent smaller than twice thereof. In addition,a protrusion portion 204 b protruding to the rear side is formed in thelower part of the rear side on the left side surface 204. A similarprotrusion portion (not shown in FIG. 5) is also formed in the lowerpart of the rear side on the right side surface 203. Parts extending inprojected shapes in the horizontal direction are formed on the frontside of the lower part of the right side surface 203 and the left sidesurface 204, thereby forming bent portions 203 a and 204 a realized byfolding the projected parts inward. In order to facilitate folding,cutout portions 203 c, 204 c, 207 a, and 208 a are formed in crookedportions on the upper side and the lower side of the bent portions 203 aand 204 a. The bent portions 203 a and 204 a and protrusion portions 203b and 204 b are formed to come into contact with the upper surface inthe vicinity of the attachment hole of the circuit board 150 forpositioning of the upper terminal component 200 in the up-downdirection.

The base body portion 201 has a substantially L-shape standing upsidedown in a side view. Flat surface portions 205 a and 206 a in which theright side surface 203 and the left side surface 204 extend forward fromparts near connection portions on the rear side in a flush surface shapeare formed in the rear parts of the arm portions 205 and 206. A gapbetween the flat surface portions 205 a and 206 a in the right-leftdirection is uniform such that they are parallel to each other. Crookedportions 205 b and 206 b that are bent inward when viewed in theright-left direction are formed in front of the flat surface portions205 a and 206 a. Again, flat surface portions 205 c and 206 c are formedon the front side of the crooked portions 205 b and 206 b. The flatsurface portion 205 c and the flat surface portion 206 c facing eachother are surfaces extending in the vertical direction and having atapered shape in which a gap on the rear side is large and is graduallynarrowed toward the front side. Fitting portions 205 d and 206 d thatare bent to expand outward at a large radius of curvature R<SUB>1</SUB>are formed in tip parts of the flat surface portions 205 c and 206 c.When curved surface parts of the fitting portions 205 d and 206 d on theinner side come into contact with the terminals of the power tool mainbodies 1 and 30, the upper terminal component 200 is electricallyconducted with the connection terminals on the power tool main bodies 1and 30 side. The inner sides of the fitting portions 205 d and 206 dhave a shape in which the battery pack 100 has a slight clearance 209 ina state of being detached from the power tool main bodies 1 and 30. Thefront sides of the fitting portions 205 d and 206 d are connected toguide portions 205 e and 206 e that are formed such that the gapsuddenly increases toward the front, thereby guiding the terminals onthe power tool main bodies 1 and 30 side. Here, surfaces of the guideportions 205 e and 206 e on the inner side have a flat surface shape.However, the surfaces may have a curved surface shape. They are formedsuch that the height in the up-down direction becomes uniform from thecrooked portion 205 b to the guide portion 205 e and from the crookedportion 206 b to the guide portion 206 e. Meanwhile, cutout portions 205f and 206 f are formed in the downward direction on the flat surfaceportions 205 a and 206 a such that the heights decrease toward the rearside. The cutout portions 205 f and 206 f are formed for the reason ofmanufacturing facilitating folding of the arm portions 205 and 206 atthe time of pressing, and for adjusting a sandwiching load (or a fittingpressure) in a set of the fitting portions 205 d and 206 d. Throughformation as described above, it is possible to realize the upperterminal component 200 that has excellent durability and is easy to use.It is preferable that the sizes of the fitting portions 205 d and 206 dof the arm portions 205 and 206 in the height direction be large as muchas possible. However, the heights of the crooked portions 205 b and 206b, the flat surface portions 205 c and 206 c, and the guide portions 205e and 206 e in the up-down direction are not necessarily uniform and maybe formed to have a shape that varies in the front-rear direction.

FIG. 5(3) is a perspective view of a single body of the lower terminalcomponent 220. Here, the region of the bridge portion 222 and parts ofleg portions 227 and 228 are illustrated by applying hatching thereto,such that the area thereof becomes clear. As it can be seen in thisdiagram, the lower terminal component 220 differs from the upperterminal component 200 in direction of being bent into a U-shape. Here,the base body portion 221 has substantially an L-shape standing uprightin a side view, and the arm portions 225 and 226 are connected to thefront side beyond the upper front sides of the right side surface 223and the left side surface 224. Parts near connection portions withrespect to the base body portion 221 of the arm portions 225 and 226 areflush with the right side surface 223 and the left side surface, andflat surface portions 225 a and 226 a of which facing surfaces areparallel to each other are formed. Crooked portions 225 b and 226 b thatare bent inward when viewed in the right-left direction are formed infront of the flat surface portions 225 a and 226 a. Again, flat surfaceportions 225 c and 226 c are formed on the front side of the crookedportions 225 b and 226 b. The flat surface portion 225 c and the flatsurface portion 226 c facing each other have a tapered shape in which agap on the rear side is large and is gradually narrowed toward the frontside. Fitting portions 225 d and 226 d that are bent at a large radiusof curvature are formed in tip parts of the flat surface portions 225 cand 226 c. When curved surfaces of the fitting portions 225 d and 226 don the inner side come into contact with the terminals of the power toolmain bodies 1 and 30, and are thus in an electrically conducting state.The inner sides of the fitting portions 225 d and 226 d have a shape inwhich the battery pack 100 has a slight clearance in a state of beingdetached from the power tool main bodies 1 and 30. The front sides ofthe fitting portions 225 d and 226 d are formed such that the gapsuddenly increases toward the front, thereby forming guide portions 225e and 226 e for guiding the terminals on the power tool main bodies 1and 30 side. Surfaces of the guide portions 225 e and 226 e on the innerside may have a flat surface shape or a curved surface shape. They areformed such that the height in the up-down direction becomes uniformfrom the flat surface portion 225 a to the guide portion 225 e and fromthe flat surface portion 226 a to the guide portion 226 e. However,similar to the arm portions 205 and 206 of the upper terminal component200, they may be formed such that the height in the up-down directionvaries excluding the fitting portions 225 d and 226 d. Through formationas described above, in the present example, it is possible to realizethe lower terminal component 220 that has excellent durability and iseasy to use.

The cutout portion 231 (refer to FIG. 5(1)) cut out into a U-shape in aside view is formed on the lower side of the arm portions 225 and 226 ofthe lower terminal component 220 from the front side toward the rearside. The cutout portion 231 is formed because a board cover 180 (whichwill be described below with reference to FIG. 11) for partitioning theupper terminal component 200 and the lower terminal component 220 isprovided in this part. The leg portions 227 and 228 are connected to thelower side of the base body portion 221. The leg portions 227 and 228are inserted into the attachment hole of the circuit board 150. The legportions 227 and 228 protrude from the attachment surface (frontsurface) of the circuit board 150 to a surface (rear surface) on a sideopposite thereto, and the protruding parts are soldered. In addition, anelectrical connection state with respect to the battery cells, theelectronic element, and the like mounted on the circuit board 150 isestablished through soldering from the arm portions 225 and 226. Here,the set of the leg portions 227 and 228 is independently wired in astate where they are not short-circuited with the set of the legportions 207 and 208 of the upper terminal component 200. The dimensionsor the shapes of the leg portions 227 and 228 are substantially the sameas those of the leg portions 207 and 208, and bent portions 223 a and224 a are formed on the front side. Cutout portions 223 c, 224 c, 227 a,and 228 a are formed on the upper side and the lower side of the crookedportions of the bent portions 223 a and 224 a. However, the cutoutportions are formed for accurate bending at the time of pressing.Therefore, the cutout portions are not necessarily provided.

Next, the shape of the terminal portion 20 on the power tool main bodies1 and 30 side and a connection state of the battery pack 100 and theconnection terminals when the battery pack 100 is mounted in the powertool main bodies 1 or 30 will be described using FIG. 6. Here, thedischarging positive electrode terminals (upper positive electrodeterminal 162 and lower positive electrode terminal 172) and the negativeelectrode terminals (upper negative electrode terminal 167 and lowernegative electrode terminal 177) of the connection terminals of thebattery pack 100 are illustrated. The LD terminals 28 and 58 (notillustrated herein) are further provided in the terminal portions 20 and50 of the power tool main bodies 1 and 30. FIG. 6(1) is a viewillustrating a state where the battery pack 100 is mounted in the 36 Vpower tool main body 30. As described above, ten battery cells areaccommodated inside the battery pack 100. Five battery cells constitutethe upper cell unit 146, and the remaining five battery cells constitutethe lower cell unit 147. Here, regarding the terminal portion, terminalportions 52 a and 57 a of a positive electrode input terminal 52 and anegative electrode input terminal 57 are smaller than the terminalportion 20 of the power tool main body 1 in the related art. That is,the width in the up-down direction is formed to be small such that theterminal portions come into contact with only the upper positiveelectrode terminal 162 and the upper negative electrode terminal 167disposed on the upper side. The positive electrode side output terminalof the upper cell unit 146 is connected to the upper positive electrodeterminal 162, and the negative electrode side output terminal isconnected to the lower negative electrode terminal 177. Meanwhile, thepositive electrode side output terminal of the lower cell unit 147 isconnected to the lower positive electrode terminal 172, and the negativeelectrode side output terminal is connected to the upper negativeelectrode terminal 167. That is, two sets of positive electrode terminaland negative electrode terminal are provided independently. One terminalset (upper positive electrode terminal 162 and lower negative electrodeterminal 177) crossing in the right-left direction and in the verticaldirection is connected to the upper cell unit 146, and the otherterminal set (lower positive electrode terminal 172 and upper negativeelectrode terminal 167) is connected to the lower cell unit 147. Sincethe upper positive electrode terminal 162 and the lower positiveelectrode terminal 172 are not electrically connected to each other,they are in an electrically independent state in a state where thebattery pack 100 is not mounted in the electric apparatus main body(state where the battery pack 100 is detached). Similarly, since theupper negative electrode terminal 167 and the lower negative electrodeterminal 177 are not electrically connected to each other inside thebattery pack 100, they are in an electrically independent state in astate where the battery pack 100 is not mounted in the electricapparatus main body (state where the battery pack 100 is detached). Thestate where the upper cell unit 146 and the lower cell unit 147 areelectrically independent from each other is an example of “anon-connection state” in the present disclosure.

As illustrated in FIG. 6(1), the positive electrode input terminal 52and the negative electrode input terminal 57 for receiving power areprovided in the terminal portion of the rated 36 V power tool main body30. Regarding a positional relationship at the time of mounting, thepositive electrode input terminal 52 is fitted into only the upperpositive electrode terminal 162, and the negative electrode inputterminal 57 is fitted into only the upper negative electrode terminal167. Meanwhile, a short bar 59 for connecting the lower positiveelectrode terminal 172 and the lower negative electrode terminal 177 toeach other such that they are short-circuited is further provided in theterminal portion of the power tool main body 30. The short bar 59 is ashort circuit member constituted of a metal conductive member, in whichone end side of the metal member bent into a U-shape constitutes aterminal portion 59 b fitted into the lower positive electrode terminal172, and the other end side constitutes a terminal portion 59 c fittedinto the lower negative electrode terminal 177. The terminal portion 59b and the terminal portion 59 c are connected to each other by aconnection portion 59 a. The short bar 59 is fixed such that it is castin a synthetic resin base 51 (which will be described below withreference to FIG. 7) together with a different apparatus side terminalsuch as the positive electrode input terminal 52 or the negativeelectrode input terminal 57. Since the short bar 59 is used for onlycausing the lower positive electrode terminal 172 and the lower negativeelectrode terminal 177 to be short-circuited, there is no need for theshort bar 59 to be wired to the control circuit or the like of the powertool main body.

The positive electrode input terminal 52 is formed to have a terminalportion 52 a that is a part fitted into the upper positive electrodeterminal 162 and formed to have a flat plate shape, a wiring portion 52c for soldering a lead wire performing wire connection with respect tothe circuit board side on the power tool main body 30 side, and acoupling portion 52 b that connects the terminal portion 52 a and thewiring portion 52 c to each other and constitutes a part cast in thesynthetic resin base 51. Here, the position of the wiring portion 52 cis disposed to deviate inward compared to the position of the terminalportion 52 a in the right-left direction, in order to adjust the gap ofthe wiring portion 52 c and to ensure that the coupling portion 52 b isstably held by the base 51 through casting. Moreover, right and leftcorner portions of the terminal portion 52 a on the front side areconfigured to be obliquely chamfered such that the terminal portion 52 aeasily enter a space between an arm portion 162 a and an arm portion 162b. The negative electrode input terminal 57 and the positive electrodeinput terminal 52 can be common components. When the terminal isdisposed in a state of being rotated by 180 degrees about the verticalaxis, it can be used as either the negative electrode input terminal 57or the positive electrode input terminal 52. Therefore, the negativeelectrode input terminal 57 is also formed to have a terminal portion 57a, a wiring portion 57 c, and a coupling portion 57 b connecting theseto each other. The front side corner portion (corner portion on the rearside when this component is used as the positive electrode inputterminal 52) of the terminal portion 57 a is also obliquely chamfered,such that the terminal portion 57 a easily enter a space between an armportion 167 a and an arm portion 167 b.

In FIG. 6(1), when the battery pack 100 is mounted, if the battery pack100 is relatively moved in the insertion direction with respect to thepower tool main body 30, the positive electrode input terminal 52 andthe terminal portion 59 b are inserted thereinto through the same slot122 (refer to FIG. 3) and are fitted into the upper positive electrodeterminal 162 and the lower positive electrode terminal 172. At thistime, the positive electrode input terminal 52 is press-fitted betweenthe arm portions 162 a and 162 b of the upper positive electrodeterminal 162 such that a space between the fitting portions of the upperpositive electrode terminal 162 is widened. In addition, the negativeelectrode input terminal 57 and the terminal portion 59 c are insertedthereinto through the same slot 127 (refer to FIG. 3) and are fittedinto the upper negative electrode terminal 167 and the lower negativeelectrode terminal 177. At this time, the negative electrode inputterminal 57 is press-fitted between the arm portions 167 a and 167 b ofthe upper negative electrode terminal 167 such that a space between thefitting portions of the upper negative electrode terminal 167 iswidened. Moreover, the terminal portions 59 b and 59 c of the short bar59 is press-fitted such that a space between a space between the armportions 172 a and 172 b of the lower positive electrode terminal 172and the lower negative electrode terminal 177 and a space between armportions 177 a and 177 b is widened. In addition, as illustrated in FIG.7(1), the front side corner portions of the terminal portions 52 a, 54 ato 58 a, 59 b, and 59 c are obliquely chamfered as indicated by thearrows 52 d, 54 d to 59 d, and 59 e such that they can be smoothlyinserted into a space between the arm portions of the connectionterminals on the battery pack 100 side.

The plate thicknesses of the terminal portion 52 a, the terminal portion57 a, and the terminal portions 59 b and 59 c are greater than aninitial clearance (clearance when the battery pack 100 is not mounted)of the fitting portion of each arm portion. Therefore, a predeterminedfitting pressure acts on a fitting point of each of the terminal portion52 a, the terminal portion 57 a, and the terminal portions 59 b and 59 cwith respect to the upper positive electrode terminal 162, the uppernegative electrode terminal 167, the lower positive electrode terminal172, and the lower negative electrode terminal 177. As a result of suchconnection, the apparatus side terminals (terminal portion 52 a,terminal portion 57 a, and terminal portions 59 b and 59 c) of the powertool main body 30 and the power terminals (upper positive electrodeterminal 162, upper negative electrode terminal 167, lower positiveelectrode terminal 172, and lower negative electrode terminal 177) ofthe battery packs favorably come into contact with each other in a statewhere electrical contact resistance is reduced. In this manner, theelectric apparatus main body 30 has the third terminal (52 a) that isinserted into the single slot (122) and is connected to only the firstterminal (162) of the first and second terminals (162 and 172), and thefourth terminal (59 b) that is inserted into the single slot (122) andis connected to only the second terminal (172). When the battery pack100 is connected to the electric apparatus main body 30, the first andthird terminals (162 and 52 a) are connected to each other inside thesingle slot 122 and becomes a first potential, and the second and fourthterminals (172 and 59 b) are connected to each other and becomes asecond potential different from the first potential. Similarly, sincethe pair of negative electrode terminals (167 and 177) side is also in aconnection state, the connection form in FIG. 6(1) is realized, so thatan output of series-connection of the upper cell unit 146 and the lowercell unit 147, that is, a rated voltage of 36 V is output from thebattery pack 100. The 36 V power tool main body 30 is an example of “afirst electric apparatus main body” in the present disclosure. Inaddition, the short bar 59 of the 36 V power tool main body 30 is anexample of “a series-connection circuit” in the present disclosure, anda state where the upper cell unit 146 and the lower cell unit 147 areconnected in series is an example of “a series-connection state” in thepresent disclosure.

Meanwhile, when the battery pack 100 is mounted in the 18 V power toolmain body 1 in the related art, a connection relationship is establishedas in FIG. 6(2). When the battery pack 100 is attached to the power toolmain body 1, the positive electrode input terminal 22 is press-fittedsuch that both opening end portions of the upper positive electrodeterminal 162 and the lower positive electrode terminal 172 are widened.Then, a region of a part of the positive electrode input terminal 22 onthe upper side comes into contact with the upper positive electrodeterminal 162, a region of a part thereof on the lower side comes intocontact with the lower positive electrode terminal 172. The same appliesto the negative electrode input terminal 27. In this manner, thepositive electrode terminals 162 and 172 are in a short-circuited stateby being fitted into the arm portions 162 a and 162 b of the upperpositive electrode terminal 162 and the arm portions 172 a and 172 b ofthe lower positive electrode terminal 172 at the same time, and anoutput of parallel-connection of the upper cell unit 146 and the lowercell unit 147, that is, a rated voltage of 18 V is output to the powertool main body 1. The positive electrode input terminal 22 and thenegative electrode input terminal 27 are formed of a metal plate havinga uniform thickness. Therefore, it is important that a fitting pressuredue to the arm portions of the upper positive electrode terminal 162 andthe upper negative electrode terminal 167, and a fitting pressure due tothe arm portions of the lower positive electrode terminal 172 and thelower negative electrode terminal 177 be equivalent to each other. Inaddition, in order to make the fitting pressures uniform, thethicknesses of the positive electrode input terminal 52 and the negativeelectrode input terminal 57 of the 36 V power tool main body 30illustrated in FIG. 9(1), and the terminal portions 59 b and 59 c of theshort bar 59 are set to be the same as the thicknesses of the positiveelectrode input terminal 22 and the negative electrode input terminal 27of the 18 V power tool main body 1 in the related art. The 18 V powertool main body 1 is an example of “a second electric apparatus mainbody” in the present disclosure. In addition, the positive electrodeinput terminal 22 and the negative electrode input terminal 27 of the 18V power tool main body 1 are examples of “a parallel-connection circuit”in the present disclosure, and a state where the upper cell unit 146 andthe lower cell unit 147 are connected in parallel is an example of “aparallel-connection state” in the present disclosure.

As described above, in the battery pack 100 of the present example,since the output of the battery pack 100 is automatically switched whenthe battery pack 100 is mounted in the 18 V power tool main body 1 orthe 36 V power tool main body 30, a convenient battery pack 100supporting a plurality of voltages can be realized. This voltageswitching is not performed on the battery pack 100 side but isautomatically performed depending on the shape of the terminal portionon the power tool main bodies 1 and 30 side. Therefore, there is nopossibility of occurrence of erroneous voltage setting. In addition,since there is no need to provide a dedicated voltage switchingmechanism such as a mechanical switch on the battery pack 100 side, itis possible to realize a long-life battery pack with a simple structureand less possibility of malfunction. Since the short bar 59 causing thelower positive electrode terminal 172 and the lower negative electrodeterminal 177 to be short-circuited can be mounted within the same spaceas the existing terminal portion 20 of the 18 V battery pack, it ispossible to realize a voltage switchable battery pack having acompatible size with those in the related art. Moreover, when chargingis performed using an external charging device, charging can beperformed by the connecting method as in FIG. 6(2). Therefore, there isno need to prepare a charging device that performs charging of both ahigh voltage and a low voltage. When the battery pack 100 is chargedusing an external charging device (not illustrated), charging can beperformed using the same charging device as that for the 18 V batterypack in the related art. In such a case, the terminal of the chargingdevice has the shape equivalent to that in FIG. 6(2). However, insteadof the discharging positive electrode terminals (162 and 172), thecharging positive electrode terminal (upper positive electrode terminal161 and lower positive electrode terminal 171) are connected to thepositive electrode terminals of the charging device (not illustrated).At this time, the connection situation is also substantially equivalentto the connection relationship illustrated in FIG. 6(2). In this manner,charging is performed using an 18 V charging device in a state where theupper cell unit 146 and the lower cell unit 147 are connected inparallel. Therefore, in a case of charging the battery pack 100 of thepresent example, a new charging device does not have to be prepared.

FIG. 7(1) is a perspective view of a terminal portion 50 of the powertool main body 30 of the present example. The terminal portion 50 ismanufactured by casting four metal connection terminals 54 to 56 and 58in the synthetic resin base 51, in addition to the positive electrodeinput terminal 52, the negative electrode input terminal 57, and theshort bar 59 illustrated in FIG. 6(1). Regarding the shapes of theconnection terminals 54 to 56 and 58, parts of coupling portions 52 band 57 b of the positive electrode input terminal 52 and the negativeelectrode input terminal 57 in FIG. 6(1) are formed linearly, terminalportions 54 a to 56 a and 58 a fitted into the connection terminals onthe battery pack 100 side are formed on one side, wiring portions 54 cto 56 c and 58 c for soldering the lead wires are formed while holes areformed on the other side, and connection portions 54 b to 56 b and 58 bthat connect the terminal portions and wiring portions to each other andare cast in a synthetic resin are formed. The base 51 firmly holds theterminal portions 52 a, 54 a to 56 a, and 58 a such that all the upperside portions of the terminal portions 52 a and 54 a to 58 a and all therear side portions are cast. In addition, regarding the terminalportions 54 a to 56 a and 58 a, a part of the lower side portion on therear side is cast. In the short bar 59 of which the shape is illustratedin FIG. 6(1), the entire connection portion 59 a (refer to FIG. 6)extending in the right-left direction is cast in the base 51, and frontparts of the terminal portions 59 b and 59 c are exposed to the frontside from the base 51. In addition, since a portion below a part on therear side exposed to the outside of the terminal portions 59 b and 59 cis cast in the base 51, the terminal portions 59 b and 59 c are firmlyheld such that they do not move in the right-left direction. In thismanner, a plurality of plate-shaped apparatus side terminals aredisposed side by side in the terminal portion 50. Here, the terminalportion 52 a and the terminal portion 59 b are disposed to be away fromeach other with a uniform clearance 53 a therebetween in the up-downdirection. In a similar manner, the terminal portion 57 a and theterminal portion 59 c are disposed to be away from each other with auniform clearance 53 b therebetween in the up-down direction.

FIG. 7(2) is a view illustrating a connection situation of the terminalportion 50 and the power terminals (162, 172, 167, and 177) of thebattery pack 100. The upper positive electrode terminal 162 has two armportions 162 a and 162 b (corresponding to the arm portions 205 and 206in FIG. 5(1)), and the lower positive electrode terminal 172 has two armportions 172 a and 172 b (corresponding to the arm portions 225 and 226in FIG. 5(1)). The arm portions 162 a and 162 b of the upper positiveelectrode terminal 162 are connected to each other such that theterminal portion 52 a formed to have a plate shape is laterallysandwiched therebetween. At the time of this joining, the arm portions162 a and 162 b are bent apart from each other in the right-leftdirection, so that a predetermined sandwiching load (fitting pressure)is applied to the terminal portion 52 a due to a restoring force ofspring action. As a result, the arm portions 162 a and 162 b and theterminal portion 52 a favorably come into surface contact or linecontact with each other. Therefore, favorable conductivity havingextremely small contact resistance can be realized. In a similar manner,the arm portions 167 a and 167 b of the upper negative electrodeterminal 167 are fitted such that the terminal portion 57 a formed tohave a plate shape is laterally sandwiched therebetween.

The arm portions 172 a and 172 b of the lower positive electrodeterminal 172 are fitted such that the terminal portion 59 b formed tohave a plate shape is laterally sandwiched therebetween. At the time ofthis fitting, the arm portions 172 a and 172 b are bent apart from eachother in the right-left direction, so that a predetermined sandwichingload (fitting pressure) is applied to the terminal portion 59 b due to arestoring force of spring action. As a result, the arm portions 172 aand 172 b and the terminal portion 59 b favorably come into surfacecontact or line contact with each other. Therefore, favorableconductivity can be realized without having contact resistance. In asimilar manner, the arm portions 177 a and 177 b of the lower negativeelectrode terminal 177 are fitted such that the terminal portion 59 cformed to have a plate shape is laterally sandwiched therebetween.

In the present example, it is important that a non-contact state betweenthe connection part of the terminal portion 52 a and the upper positiveelectrode terminal 162, and the connection part of the terminal portion59 b and the lower positive electrode terminal 172 be retained and thatan electrically insulating state be maintained. In addition, it isimportant that a non-contact state between the connection part of theterminal portion 57 a and the upper negative electrode terminal 167, andthe connection part of the terminal portion 59 c and the lower negativeelectrode terminal 177 be retained and that an electrically insulatingstate be maintained. In such a configuration, even when the battery pack100 vibrates in a resonance frequency different from that of the powertool main body 30 due to various vibrations or shocks occurring whilethe power tool is in use, occurrence of a short circuit between theupper positive electrode terminal 162 and the lower positive electrodeterminal 172 can be inhibited, and occurrence of a short circuit betweenthe upper negative electrode terminal 167 and the lower negativeelectrode terminal 177 can be inhibit. In FIG. 7(2), illustration of theconnection terminals on the battery pack side to be fitted into theterminal portions 54 a to 56 a and 58 a is omitted. However, when thepower terminals on the positive electrode side (upper positive electrodeterminal 162 and lower positive electrode terminal 172) and the powerterminals on the negative electrode side (upper negative electrodeterminal 167 and lower negative electrode terminal 177) are connected toeach other, the signal terminals (T terminal 164, V terminal 165, LSterminal 166, and LD terminal 168 illustrated in FIG. 4) are similarlyfitted into the terminal portions 54 a to 56 a and 58 a.

FIG. 8(1) is a perspective view of the terminal portion 20 of the powertool main body 1 in the related art, and FIG. 8(2) is a viewillustrating a connection situation of the power terminals of thebattery pack 100. The terminal portion 20 is manufactured by casting sixmetal terminals 22 and 24 to 28 in a synthetic resin base 21. Regardingthe shapes of the terminals 22 and 24 to 28, as in FIG. 6(2)illustrating a part of the terminals 22 and 27 before casting, theterminal portions 22 a and 24 a to 28 a fitted into the connectionterminals on the battery pack 100 side are formed on one side, thewiring portions for soldering the lead wires are formed while holes areformed on the other side, and connection portions 22 c and 24 c to 28 cthat connect the terminal portions and wiring portions to each other andare cast in a synthetic resin of the base 21 are formed. The base 21firmly holds the terminal portions 22 a and 24 a to 28 a such that allthe upper side portions of the terminal portions 22 a and 24 a to 28 a,all the rear side portions, and part of the lower side portions on therear side are cast. The front side corner portions of the terminalportions 22 a and 24 a to 28 a are obliquely chamfered as indicated bythe arrows 22 d and 24 d to 28 d such that they can be smoothly insertedinto a space between the arm portions of the connection terminal on thebattery pack 100 side. Regarding the shape of the terminal portion 20, agroove portion 21 b extending in the right-left direction is formed onthe front side of the base 21, and a groove portion 21 c extending inthe right-left direction is similarly formed on the rear side. Thegroove portions 21 b and 21 c are pinched in an opening part of thehousing in the terminal portion 20.

FIG. 8(2) is a view illustrating a connection situation of the terminalportion 20 and the power terminals (162, 172, 167, and 177) of thebattery pack 100. Here, illustration of the signal terminals (T terminal164, V terminal 165, LS terminal 166, and LD terminal 168) on thebattery pack 100 side is omitted. The arm portions 162 a and 162 b ofthe upper positive electrode terminal 162 are fitted such that an upperregion of a terminal portion 22 a formed to have a plate shape islaterally sandwiched therebetween. At the time of this fitting, the armportions 162 a and 162 b are bent apart from each other in theright-left direction, so that a predetermined sandwiching load (fittingpressure) is applied to the terminal portion 22 a due to a restoringforce of spring action. In addition, the arm portions 172 a and 172 b ofthe lower positive electrode terminal 172 are fitted such that the lowerpart of the terminal portion 22 a formed to have a plate shape islaterally sandwiched therebetween. Each of the arm portions 167 a, 167b, 177 a, and 177 b of the upper negative electrode terminal 167 and thelower negative electrode terminal 177 of the power terminals is in asimilar fitting state. In this manner, four arm portions 162 a, 162 b,172 a, and 172 b come into contact with one terminal portion 22 a. In asimilar manner, on the negative electrode side as well, the arm portions167 a and 167 b of the upper negative electrode terminal 167 are fittedsuch that the upper region of a terminal portion 27 a formed to have aplate shape is laterally sandwiched therebetween, and the arm portions177 a and 177 b of the lower negative electrode terminal 177 are fittedsuch that the lower part of the terminal portion 27 a is laterallysandwiched therebetween. In this manner, four arm portions 162 a, 162 b,172 a, and 172 b come into contact with one terminal portion 22 a. In asimilar manner, four arm portions 167 a, 167 b, 177 a, and 177 b comeinto contact with the terminal portion 27 a. Therefore, these canfavorably come into surface contact or line contact with each other, sothat favorable conductivity can be realized without having contactresistance.

Next, the shape of components used for three terminals (164 to 166),that is, a signal terminal component 240 will be described using FIG. 9.The signal terminal component 240 is manufactured by pressing one metalplate. From a base body portion 241 realized by bending a thin metalplate such that a bridge portion 242 constituting a U-shaped bottom partbecomes a vertical surface on the rear side, the arm portion set (armportion base portions 245 and 246) extends to the front side. The armportion base portion 245 is formed to apart as an arm portion sets onthe upper and lower side (arm portions 251 and 253), and since a cutoutgroove 244 b extending in the horizontal direction is formed, the armportion base portion 246 is formed to apart as an arm portion sets onthe upper and lower side (252 and 254). A metal plate used in pressingis a flat plate having a thickness of 0.3 mm and it may be thinner thanthe plate thickness of 0.5 mm of the upper terminal component 200 andthe lower terminal component 220 used for the power terminals. The armportion sets on the upper side and the lower side are formed to have thesame shape as each other, and the length in the front-rear direction,the width in the up-down direction, the plate thickness, and the likeare the same as each other. The fitting portions (251 d, 253 d, and thelike) are formed in each of the arm portion set (arm portions 251 and252) on the upper side and the arm portion set (arm portions 253 and254) on the lower side. However, the upper and lower shapes curved forthe fitting portions are also the same as each other, and the right andleft arm portions have plane-symmetrical shapes. Meanwhile, attachmentpositions of leg portions 249 and 250 are disposed to significantlydeviate in the front-rear direction. The shape of the lower part of thebase body portion 241 is different on the right and left, so that aright side surface 243 and a left side surface 244 have asymmetricalshapes. The leg portion 249 is disposed to significantly deviate forwardcompared to a position of a leg portion 250 in the related art, and theleg portions 249 and 250 are significantly distanced away from eachother in the front-rear direction. In this manner, since the leg portion249 and the leg portion 250 are disposed to deviate forward and rearwardinstead of being side by side adjacent to each other in the right-leftdirection, an extension portion 243 a significantly extending forward isformed near a lower side of the right side surface 243, and the legportion 249 is formed to extend in the downward direction from a frontend part. Each of the leg portion 249 and the leg portion 250 is fixedto the circuit board 150 by penetrating the penetration hole (notillustrated) formed in the circuit board 150 from the front surface tothe rear surface side and soldering the part protruding to the rearsurface side, and the arm portion set (arm portions 251 and 252) on theupper side and the arm portion set (arm portions 253 and 254) on thelower side are electrically connected to the electronic element mountedin the circuit board 150.

A bent portion 243 b that limits the insertion amount of the circuitboard 150 in the attachment hole 151 (refer to FIG. 4) and is folded inthe left direction is formed above the leg portion 249. Cutout portions243 c and 249 a that are cut out into semicircular shapes in order tofacilitate folding are formed on the upper side and the lower side ofbent parts of the bent portion 243 b. Stepped portions 250 a and 250 bformed on the front side and the rear side of the leg portion 250 areused for positioning of the leg portion 250 on the rear side withrespect to the circuit board 150. The stepped portion 250 a is formed bycausing the lower part of the left side surface 244 to extend forward,and the stepped portion 250 b is formed by utilizing the lower sideportion of the bridge portion 242 curving in a U-shape. In this manner,when the stepped portions 250 a and 250 b abut the front surface of thecircuit board 150, the attachment position of the leg portion 250 in theup-down direction can be determined. The attachment positions of the legportions 249 and 250 in the front-rear direction are regulated by theposition of the attachment hole 151 (refer to FIG. 4) in the circuitboard 150.

FIG. 9(2) is a view of a single body of the signal terminal component240 viewed from the front lower side. As it can be seen from thisdiagram, since a cutout groove 245 b extending in the horizontaldirection is formed on the front side of the arm portion base portion245, the arm portion set is separated as the upper and lower armportions (arm portions 251 and 253). In addition, the leg portion 249 onthe right side is disposed to significantly deviate forward compared tothe leg portion 250 on the left side. As a result, even if a force isapplied to four arm portions 251, 252, 253, and 254 in the upwarddirection or the downward direction, the signal terminal component 240can be firmly held in the circuit board. An external force applied tothe arm portions 251, 252, 253, and 254 is applied such that the armportion set is pushed to the rear side when the battery pack 100 ismounted in the power tool main bodies 1 and 30, and this force acts in adirection of tilting the signal terminal component 240 rearward. On thecontrary, when the battery pack 100 is detached from the power tool mainbodies 1 and 30, it becomes a force pushing the arm portion set to thefront side, and this force acts in a direction tilting the signalterminal component 240 forward. In this manner, an external force thatis applied when the battery pack 100 is mounted and detached can beeffectively received by causing the positions of the leg portions 249and 250 to deviate in the front-rear direction, and the attachmentrigidity of the signal terminal component 240 can be strengtheneddrastically, so that durability of the battery pack 100 can be enhanced.Moreover, the arm portion set is also formed apart in two stages on theupper side and the lower side. Therefore, even if various vibrations arereceived or an external force is received during an operation of thepower tool, a favorable contact state with respect to the terminals onthe power tool main body side can be maintained due to four contactregions of the arm portions. Meanwhile, since the number of attachmentholes and the number of soldering places in the circuit board 150required when this signal terminal component 240 is manufactured are thesame as those in the related art, increase in manufacturing cost can besuppressed.

The signal terminal component 240 of the present example exhibitsanother effect in addition to improvement in rigidity. In the signalterminal component in the related art (not illustrated), leg portions tobe soldered to the circuit board and to be electrically and mechanicallyattached are provided at two places. However, the leg portions arearranged in the right-left direction, and there are many cases where thespace between the leg portions is small and solder parts are connectedto each other, so that it is not possible to perform wiring in which asignal pattern passes through a space between the right and left legportions. In the battery pack 100 of the present example, one legportion 249 of the signal terminal component 240 is disposed on thefront side and the other leg portion 250 is disposed on the rear side,such that both the leg portions are disposed apart from each other.Accordingly, the distance between the leg portions of the signalterminal component 240 increases, so that it is possible to easily lay aplurality of wirings or to perform wiring of thick pattern in which amain current flows. Such a signal terminal component 240 is preferablewhen it is desired to achieve a high function in the battery pack 100 ofthe present example, that is, the battery pack in the related art and topromote miniaturization in voltage ratio. Particularly, when a voltageswitching function is realized after the voltage is raised, the numberof electronic elements to be mounted in the circuit board 150 increases.Here, there is a need to achieve efficient pattern wiring and to thickenthe wiring in which the main current flows. In the present example, thecircuit board 150 larger than that used in the related art is used, sothat the electronic elements are mounted not only on the rear side ofthe connection terminal group but also in the front region. At thistime, wiring patterns are also disposed on the lower side of the signalterminal component 240. A disposition method thereof will be describedusing FIG. 10.

FIG. 10 is a view illustrating a situation of fixing a plurality ofsignal terminal components 240 to the circuit board 150. FIG. 10(1) is aview viewed from the front, and FIG. 10(2) is a view of the signalterminal component 240 viewed from the left. The signal terminalcomponents 240 are common components and are fixed side by side as the Tterminal 164, the V terminal 165, and the LS terminal 166 in theright-left direction with a distance S4 therebetween on the circuitboard 150. Since a cutout portion 255 (refer to FIG. 9(2)) is formed togenerate a gap S2 near the center of the arm portion, the signalterminal component 240 has a shape in which the arm portion set (251 and252) on the upper side and the arm portion set (253 and 254) the lowerside are present in two stages on the upper and the lower side. In astate where no apparatus side terminal is mounted, parts (fittingportions) closest to the arm portion set (251, 252) on the upper sideand the arm portion set (253 and 254) on the lower side are disposedwith a slight clearance therebetween or in an abutting manner. Each ofthe leg portions 249 and 250 penetrates the attachment hole (refer toFIG. 4) of the circuit board 150, protrudes to the lower side, and isfixed by a solder 256 on the lower side (rear surface) of the circuitboard 150.

In the side view of FIG. 10(2), the leg portion 249 positioned on thefront side and the leg portion 250 positioned on the rear side areconfigured to be apart from each other by a distance S3. It is favorablethat the distance S3 be larger than the gap (distance in the right-leftdirection) with respect to the leg portions 249 and 250. In this manner,when the clearance indicated by the arrow 257 is formed, it is easy toperform wiring of a circuit pattern in this clearance part. FIG. 10(3)is a bottom view of the circuit board 150 in FIG. 10(1) viewed from alower side. The penetration hole for soldering the signal terminalcomponent 240 is formed at the center on the rear surface of the circuitboard 150, and lands 153 a to 155 a and 153 b to 155 b in which soldercopper foils having a substantially quadrangular shape are disposed areformed around the penetration hole. Connection wiring patterns from thelands 153 a to 155 a and 153 b to 155 b to the upper cell unit 146 orthe lower cell unit 147 are provided on the front surface side of thecircuit board 150 and are not shown in the diagram of FIG. 10(3). Theleg portion lands 153 a to 155 a on the left side and the leg portionlands 153 b to 155 b on the right side are disposed to deviate forwardand rearward. As a result, a plurality of patterns 157 to 159 can bedisposed between the lands 153 a to 155 a and the lands 153 b to 155 bas in the diagram. Here, the wiring patterns 157 to 159 are illustratedto be provided three for each. However, the wiring pattern may berealized in one thick wiring or may be a combination of a differentnumber of patterns. In this manner, a wiring pattern is disposed betweenthe leg portions 249 and 250 disposed to deviate in the front-reardirection. Therefore, while the same gap as that in the related art ismaintained between the signal terminals 164 and 165, and 165 and 166adjacent to each other, it is possible to provide a plurality of wiringpatterns 157 to 159 connecting the rear side and the front side of thesignal terminals 164 to 166 to each other. As another method ofincreasing the number of wiring patterns connecting the rear side andthe front side of the signal terminals 164 to 166 to each other, amethod of providing a cutout portion 243 c as indicated by the dottedline in FIG. 10(2) may be used together. The cutout portion 243 c cutout upward as indicated by the dotted line is formed near a lower sideof the right side surface 243, that is, in a part in contact with thecircuit board 150. Consequently, a part indicated by the arrow 257becomes a gap to be distanced away from the circuit board 150. Similarto the wiring patterns 157 to 159 in FIG. 10(3), a circuit pattern canbe disposed between this gap and the circuit board 150. In this manner,it is possible to dispose a plurality of wiring patterns connecting therear side and the front side of the signal terminals 164 to 166 not onlyon a rear surface side 150 b but also on a front surface side 150 a ofthe circuit board. Therefore, execution efficiency of the circuit board150 can be improved.

FIG. 11 is a view illustrating shapes of the connection terminal group(161 to 162 and 164 to 168) and the board cover 180 disposed aroundthereof. FIG. 11(1) is a perspective view, and FIG. 11(2) is a frontview. Here, illustration of the circuit board 150 is omitted forunderstanding of the disclosure. In an actual product, a plurality ofconnection terminal groups (161 to 162, 164 to 168, 171, 172, and 177)are fixed to the circuit board 150 through soldering. Thereafter, theboard cover 180 is attached around the connection terminals. The powerterminals (161, 162, and 167) are formed to be higher than the signalterminals (164 to 166 and 168) in the upward direction by a distance H.The board cover 180 is a member that is manufactured using anon-conductor, for example, a synthetic resin molded article and coversan area around the leg portions of the connection terminals adjacent toeach other. The board cover 180 has a coupling portion 181 having a flatsurface-shaped upper surface 181 a on the front side, and a plurality ofpartitioning walls 182, 183, and 184 to 189 are connected to the rearside of the coupling portion 181. The partitioning walls 182, 183, and184 to 189 are disposed on the rear side of the flat surface portion 181a, that is, in the right and left parts of the connection terminal groupand thus performs a function in which an electrical short circuit isunlikely to occur between the connection terminals. In addition, theupper surface 181 a of the coupling portion 181 is formed to be flushwith the upper stage surface 115 (refer to FIG. 3) of the upper casing110, so that a main body side terminal portion can easily performrelative movement from the upper stage surface 115 to the couplingportion 181. In addition, a covered portion 184 blocking an opening inan unused region (slot 123 in FIG. 3) is provided in the board cover180, such that waste or dust is unlikely to enter the inside of thecasing of the battery pack 100 through the slot 123.

The board cover 180 is formed to mainly include the coupling portion 181having the upper surface 181 a that is horizontal in the lateraldirection, and a plurality of partitioning wall portions extendingthereabove. Partitioning walls 185, 186, and 189 of the partitioningwall portions disposed between the signal terminals constitute low wallportions having a height H2, and the upper end positions thereof becomepositions lower than the signal terminals (164 to 166) and the armportions of the LD terminal 168 on the lower side. In contrast, powerterminal partitioning walls 182, 183, 184 a, 187, and 188 adjacent toeach other constitute high wall portions having a height H3 from theupper surface 181 a. The upper end positions thereof are configured tobe positions above the upper end position of the lower terminalcomponent and positions on the lower side of the arm portions of theupper terminal component.

In the power terminals of the connection terminal group, as describedwith reference to FIG. 5 to FIG. 8, the leg portions of the upperpositive electrode terminals 161 and 162 and the lower positiveelectrode terminals 171 and 172 are arranged in the front-reardirection, and the arm portion sets thereof are disposed side by side inthe up-down direction. In a similar manner, the leg portions of theupper negative electrode terminal 167 and the lower negative electrodeterminal 177 are arranged in the front-rear direction, and the armportion sets thereof are disposed side by side in the up-down direction.When the battery pack 100 is mounted in a rated 18 V electric apparatusmain body, the potentials of the arm portions of the upper positiveelectrode terminal 162 and the upper negative electrode terminal 167become the same as the potentials of the lower positive electrodeterminal 172 and the lower negative electrode terminal 177. Therefore,there is no problem even if the upper terminal component and the lowerterminal component come into contact with each other. However, when thebattery pack 100 is mounted in a rated 36 V electric apparatus mainbody, the potentials of the upper positive electrode terminal 162 andthe upper negative electrode terminal 167 differ from the potentials ofthe lower positive electrode terminal 172 and the lower negativeelectrode terminal 177. Therefore, it is important that ashort-circuited state due to contact between the upper and lower armportions be not generated. In addition, it is favorable to have a shapesuch that a short circuit caused by insertion of a foreign substance isunlikely to occur. Here, in the board cover 180 of the present example,regarding the partitioning walls 182, 183, 184 a, 187, and 188 of thepartitioning wall portions formed to extend in the upward direction fromthe coupling portion 181, the upper end positions are formed high aboveto reach a height H3. In addition, not only the wall portions extendingupward in the vertical direction but also horizontal wall portionsextending in the right-left direction from the upper end positions ofvertical wall portions are formed.

FIG. 11(3) is an enlarged view of a part of the board cover 180 in FIG.11(2) and is a view excluding illustration of a connection terminalpart. The partitioning wall 182 has a vertical wall portion 182 a and ahorizontal wall portion 182 b, and the cross-sectional shape thereofbecomes an L-shape. The horizontal wall portion 182 b has a shapeextending in the horizontal direction to reach the inside of a spacebetween the arm portions of the power terminals (upper positiveelectrode terminal 161 and lower positive electrode terminal 171)adjacent to each other from a part near the upper end of the verticalwall portion 182 a. In addition, the partitioning wall 183 has aT-shaped cross-sectional shape and is formed to have a vertical wallportion 183 a and horizontal wall portions 183 b and 183 c extending inboth directions from the upper end portion of the vertical wall portion183 a. The horizontal wall portion 183 b extends to a side approachingthe horizontal wall portion 182 b adjacent thereto and has a length suchthat the tip thereof reaches the inside of the space between the armportions of the upper positive electrode terminal 161 and the lowerpositive electrode terminal 171. In a similar manner, the horizontalwall portion 183 c extends to a side approaching the horizontal wallportion 184 b adjacent thereto and has a length such that the tipthereof reaches the inside of the space between the arm portions of theupper positive electrode terminal 162 and the lower positive electrodeterminal 172. A situation in which the horizontal wall portions 182 b,183 b, and 183 c extend to the inside of the space between this armportions is clear as seen in the positive electrode terminal groupviewed from the front as illustrated in FIG. 11(2). For example, theposition of the right side surface of the upper positive electrodeterminal 161 and the position of the right side surface of the lowerpositive electrode terminal 171 are the same position. However, the leftend position 182 c of the horizontal wall portion 182 b has a length toan extent that it enters the lower part of an arm portion 161 a of theupper positive electrode terminal 161 to extend to the left side beyondthe positions of the left side surfaces of the upper positive electrodeterminal 161 and the lower positive electrode terminal 171. Thehorizontal wall portion 182 b is positioned on the upper side of an armportion 171 a of the lower positive electrode terminal 171.

The lengths of the vertical wall portion 182 a and the horizontal wallportion 182 b in the front-rear direction are formed to be longer thanthe length of the lower positive electrode terminal 171 in thefront-rear direction, and the front end positions thereof aresubstantially the same position as the tip of the arm portions of thelower positive electrode terminal 171, and the rear end positions are onthe rear side of the rear end position of the lower positive electrodeterminal 171. In this manner, the vertical wall portion 182 a covers theentire right side surface of the lower positive electrode terminal 171and also covers the upper side part excluding a part near the center inthe right-left direction (part of a distance S5). Moreover, the verticalwall portion 183 a covers the entire left side surface of the lowerpositive electrode terminal 171 and the entire right side surface of thelower positive electrode terminal 172, and also covers the upper sidepart excluding a part near the center in the right-left direction. Here,only the shapes of the vertical wall portion 182 a and the horizontalwall portion 182 b of the lower positive electrode terminal 171 part arementioned. However, regarding the lower positive electrode terminal 172as well, since the partitioning walls 183 and 184 covering the entireright side surface, the entire left side surface, and the upper sidepart excluding the central part are provided, even if an external forceis applied to the lower positive electrode terminals 171 and 172 so thata force of bending this is applied, lower positive electrode terminals171 and 172 can be effectively held by the board cover 180, and thus itis possible to drastically reduce a possibility that a powertransmission terminal component on the lower side and the terminalcomponent on the upper side may be unintentionally short-circuited.

Based on the same idea as the positive electrode terminal sides (161,162, 171, and 172), in the negative electrode terminal sides (167 and177) as well, the large partitioning walls 187 and 188 are provided onboth right and left sides of the negative electrode terminal. Thepartitioning wall 187 has a shape similar to that of the partitioningwall 182, is formed to have the vertical wall portion 187 a and thehorizontal wall portion 187 b, and has an L-shaped cross section. Thehorizontal wall portion 187 b is formed to extend from upper end part ofthe vertical wall portion 187 a to the negative electrode terminal side.The partitioning wall 188 is formed to have bilateral symmetry with thepartitioning wall 187 and is formed to have the vertical wall portion188 a and the horizontal wall portion 188 b. The horizontal wallportions 187 b and 188 b have sizes such that the tip parts enter thespace between the arm portion set of the upper negative electrodeterminal 167 and the arm portion set of the lower negative electrodeterminal 177. However, the horizontal wall portions 187 b and 188 b havea predetermined gap S5 to prevent entrance of an apparatus side terminalsuch as the power tool main bodies 1 and 30 from being hindered. In thismanner, since the partitioning walls 187 and 188 are formed to cover thearea around the negative electrode terminals (167 and 177) serving asthe power terminals, even if a strong external pressure is applied tothe upper negative electrode terminal 167 or the lower negativeelectrode terminal 177 and it moves (is bent) in the front-reardirection, it is possible to drastically reduce a possibility ofoccurrence of a short circuit phenomenon due to the presence of the wallportions such as the horizontal wall portions 187 b and 188 b.

The partitioning walls 185 and 186 between the signal terminal groups(164 to 166) only have a small height H2 in the upward direction. Thisis because since only signals using small power flow in the signalterminal groups (164 to 166), the risk degree at the time of a shortcircuit is drastically smaller than that on the power terminal side. Inaddition, each of the signal terminal groups (164 to 166) constitutesone component, and the arm portions on the upper side and the armportions on the lower side have the same potentials. Therefore, there isless need to worry about a short circuit. The same applies to thepartitioning wall 189 as well. The partitioning wall 184 includes thevertical wall portions 184 a and 184 d, which are connected to eachother by a closing plate 184 c. The closing plate 184 c is a flat plateextending in the vertical direction and the right-left directions andexhibits a function of closing a free space (internal space of the freeslot 123 in FIG. 3) between the upper positive electrode terminal 162and the lower positive electrode terminal 172, and the T terminal 164.The horizontal wall portion 184 b extending to the positive electrodeterminal side is formed near the upper end of the vertical wall portion184 a.

The coupling portion 181 fixes the vertical wall portions 182 a, 183 a,184 a, 184 d, 185 a, 186 a, 187 a, and 188 a positioned between theconnection terminals by being connected to the front surfaces thereof.The wall portion of the upper surface 181 a of the coupling portion 181is formed to be in a state higher than the circuit board 150. The innerpart (lower part) of the coupling portion 181 is formed to have a space,and the vertical wall portions 184 a, 185 a, 186 a, and 187 a aredisposed on the rear side thereof. Here, although they are hidden behindthe front wall surface 181 b, the vertical wall portions 182 a, 183 a,184 d, and 188 a are similarly formed to extend to the lower side and tocome into contact with the circuit board 150. The inner part of thiscoupling portion 181 is solidified after being filled with a curableliquid resin (which will be described below with reference to FIG. 13)covering the upper surface of the circuit board 150. Due tosolidification of the curable resin, parts near the lower ends of theplurality of vertical wall portions 182 a, 183 a, 184 a, 184 d, 185 a,186 a, 187 a, and 188 a and the circuit board 150 are firmly fixed.Three cutout portions 181 c to 181 e are formed on the front wallsurface 181 b of the coupling portion 181. The cutout portions 181 c to181 e are formed such that a liquid resin (which will be described belowwith reference to FIG. 13) equally reaches the rear part and the frontpart of the circuit board 150. Since the viscosity of the liquid resinis relatively low, the resin flows in the front-rear direction throughspaces between the cutout portions 181 c to 181 e (details will bedescribed below).

FIG. 12 is a view illustrating only the upper casing 110 extracted fromFIG. 3 and is a view for describing the shape of the upper stage surface115 of the upper casing 110. FIG. 12(1) is a perspective view of theupper casing 110, and FIG. 12(2) is an arrow view viewed in the arrow Bdirection in FIG. 12(1). In FIG. 12(1), stepped parts are illustrated byapplying hatching thereto, such that the area thereof becomes clear. Asdescribed with reference to FIG. 11, the power terminals (161, 162, and167) are formed to be higher than the signal terminals (164 to 166 and168) in the upward direction by a distance H. This is because the powerterminals are formed of a thicker plate material than the signalterminals. Therefore, in the shape of the upper stage surface of theupper casing in the related art, the upper end portions of the powerterminals (161, 162, and 167) interfere with the inner wall on the upperstage surface. Here, in the present example, the position of the innerwall surface of the upper stage surface 115 of the upper casing 110viewed in the up-down direction is configured to partially deviateupward such that clearances of the upper portions of the power terminals(161, 162, and 167) are ensured. It is also conceivable that a method inwhich only the position of the inner wall surface constitutes a recessedportion depressed in the upward direction is employed. However, if thescreen shape of the upper stage surface 115 remains without any change,there is a possibility that the thickness of a part on the upper stagesurface 115 of the upper casing 110 may become insufficient and thestrength may deteriorate locally. Here, in the present example,protrusion portions 115 a and 115 b protruding outward are formed on theouter surface of the upper stage surface 115, that is, in the upperportion near parts where the power terminals (161, 162, and 167) arepositioned. In this manner, a part of the wall surface of the upperstage surface 115 is configured to deviate upward. Therefore, anaccommodation space can be increased in the inner part, anddeterioration in strength of the wall surface can also be prevented. Inthe present example, since a protruding height H4 of the outer wallsurface on the upper stage surface 115 is configured to be smaller thana depression height H5 of the inner wall surface, the sizes of theprotrusion portions 115 a and 115 b can be reduced on the upper stagesurface 115, so that the size is settled within a range to be able to bemounted in the power tool main body 1 in the related art withouthindrance. In addition, since a stepped portion is partially formed anda step is formed such that the height of the hatched portion becomeshigher in the upper stage surface 115 instead of being flush with othersurfaces, it is possible to achieve a strength equivalent to or greaterthan that of the upper casing having the same flat surface shape in therelated art.

Next, a method of applying a resin to the circuit board 150 will bedescribed using FIG. 13. FIG. 13 is a perspective view of the circuitboard 150. Here, although illustration is omitted, a main region 156 aand a sub-region 156 b for mounting electronic elements are provided onthe upper surface (front surface) of the circuit board 150. The mainregion 156 a is located on the rear side of the connection terminalgroup, and a protective management IC (which will be described below)including a microcomputer is mounted therein. The sub-region 156 b is aregion on the front side of the connection terminal group. Here, all theelectronic elements to be mounted are covered with a curable resin. Acurable resin is cured from a liquid state, and a urethane resin can beused, for example. In order to equally fill the upper surface of thecircuit board 150 with a liquid urethane resin, an adhesive resin 155serving as a bank preventing outflow of a liquid resin is adhered to anouter edge part of an element group mounted first in the circuit board150. Regarding the adhesive resin 155, for example, a bonding agentextracted into a columnar shape from the inside of a tube-shapedcontainer through a slender extraction port is continuously adheredalong an outer edge of the region desired to be filled with a urethaneresin. At this time, it is important that the bonding agent be adheredalong the outer edge part in a seamless manner. The adhesive resin 155is formed such that one end portion and the other end portion come intocontact with the board cover 180. In this manner, when the adhesiveresin 155 constituting the outer frame is adhered substantially aroundthe outer edge part where a resin is to be poured, thereafter, aurethane resin in a liquid state is poured on the inner side of theupper surface of the circuit board 150.

The amount of a urethane resin to be poured is set to an amountsufficiently filling the range surrounded by the adhesive resin 155. Atthis time, at a place that is not desired to be covered with a resin,the outer edge of the place is surrounded by adhesive resins 155 a to155 c, so that the resin that has been poured on the outer side thereofdoes not enter the range surrounded by the adhesive resins 155 a to 155c. If the position where the urethane resin is to be poured is set neara part indicated by the arrow 156 a in the main region, the resin doesnot flow into the range surrounded by the adhesive resin 155 a. Inaddition, in the board cover 180, in a state where the wall surface ofthe coupling portion 181 forming the upper surface 181 a is high, therear wall surface of the lower part is in an open state, and the frontside becomes the wall surface. Since the cutout portions 181 c to 181 eare formed in a part thereof, the resin can flow favorably from the mainregion 156 a to the sub-region 156 b. In this manner, when the entireelement mounting surface of the circuit board 150 is covered with aresin and the resin is cured thereafter, it is possible to cover theinside of a target range with the resin with no gap at a uniform heighton the front surface on the circuit board 150 side and to protectmounted electronic elements from influence of water or dust. When adouble-sided substrate is used as the circuit board 150, the rearsurface side may also be covered with a resin through a similarprocedure. In addition, a resin may also be applied to parts exemptedfrom filling of a resin (adhesive resin 155), for example, parts nearthe screw holes and solder portions of lead wires at the time of apost-process after screw fastening is completed and at the time of apost-process after soldering is completed.

Hereinabove, the first example of the present disclosure has beendescribed using FIG. 1 to FIG. 13. However, the battery pack 100illustrated in the first example can be subjected to variousmodifications. FIG. 14 is a view illustrating the shapes of an upperterminal component 260 and a lower terminal component 280 according to afirst modification example of the present example. FIG. 14(1) is aperspective view, FIG. 14(2) is a left-side view, and FIG. 14(3) is afront view. Each of the upper terminal component 260 and the lowerterminal component 280 has two arm portion sets (265 and 266, and 285and 286) in the right-left direction, and the configuration in which twoarm portion sets are aligned in the up-down direction is the same asthat in the first example. The configuration in which a leg portion set(267 and 268) of the upper terminal component 260 is disposed side byside with a leg portion set (287 and 288) of the lower terminalcomponent 280 in the front-rear direction is the same as that in thefirst example. In the lower part on the rear side of right side surfaces263 and 283 and left side surfaces 264 and 284, as indicated by thearrows 262 a and 282 a in FIG. 14(2), bridge portions 262 and 282protrude to be curved to the rear side. Therefore, this protruding partis used for positioning in the up-down direction when the upper terminalcomponent 260 and the lower terminal component 280 are attached to thecircuit board 150. Bent portions 263 a, 264 a, 283 a, and 284 a (here,263 a is not shown in FIG. 14) in which parts extending in projectedshapes are folded inward are formed in the front side upper portion ofthe leg portions 267 and 268, and 287 and 288. The shapes thereof aresimilar to those in the configuration of the first example illustratedin FIG. 5.

In the upper terminal component 260, the direction of being folded intoa U-shape differs from the direction indicated in FIG. 5. Here, a partconstituting a bottom portion when the upper terminal component 260 isfolded into a U-shape, that is, the bridge portion 262 is formed to be avertical surface. In the folded shape of the lower terminal component280, the direction of being folded into a U-shape is the same as thelower terminal component 220 illustrated in FIG. 5, and the bridgeportion 282 constitutes a vertical surface. The bridge portions 262 and282 are disposed in parallel to each other and have a substantiallyuniform gap in the front-rear direction, and these are disposed toextend substantially in the vertical direction with respect to the frontsurface of the circuit board 150. In the upper terminal component 260and the lower terminal component 280, the configuration in which theyare manufactured by pressing a flat metal plate is similar to that ofthe first example. However, the thickness of the flat plate is furtherincreased.

The right side surface 263 and the left side surface 264 have asubstantially rectangular shape extending in the vertical direction andare formed such that the arm portions 265 and 266 extend to the frontside in a part close to the upper end. Parts near the rear bases of thearm portions 265 and 266, that is, near a chain line B2 have asignificant width (length in the up-down direction). The width isgradually reduced as it goes forward, and the width becomes uniform onthe front side further beyond an imaginary line B1. The configuration inwhich fitting portions 265 d and 266 d are bent into a curved surfaceshape having a predetermined radius R1 of curvature on the inner side ina top view is similar to that of the first example illustrated in FIG.5. In this manner, the arm portions 265 and 266 are formed to extendforward from the upper front side portion of the U-shaped base bodyportion, and the arm portions 265 and 266 are formed to have springproperties in a non-contact state.

The lower terminal component 280 has the right side surface 283 and theleft side surface 284 that are formed by being folded into a U-shape tobe parallel to each other, and the bridge portion 282 that connectsthose to each other. The lower terminal component 280 is provided suchthat the arm portions 285 and 286 extend forward and obliquely upwardfrom slender upper portions of the right side surface 283 and the leftside surface 284. The widths of the arm portions 285 and 286 in theup-down direction are substantially uniform in the front-rear direction.The arm portions 285 and 286 are formed to extend in the horizontaldirection on the front side of the imaginary line B1 and are obliquelydisposed on the rear side of the imaginary line B1. A cutout portion 291significantly cut out from the front side is formed below the armportion set (285 and 286) of the lower terminal component 280. As aresult of such formation, the lengths (length in the front-reardirection, that is, the front side of B2) of the arm portions 265 and266 of the upper terminal component 260 become longer than the lengths(length in the front-rear direction, that is, the front side of theposition of the arrow 291) of the arm portions 285 and 286 of the lowerterminal component 280. Even in such arm portion sets having differentlengths in the front-rear direction, it is preferable that the fittingpressure in the fitting portion of the upper terminal component 260 bethe same as the fitting pressure of the lower terminal component 280. Ifthe fitting pressures are not equalized, contact resistance with respectto the flat plate-shaped apparatus side terminal on the power tool mainbodies 1 and 30 side changes, so that there is a possibility that aslight difference in heat generation may be generated or the wearsituation may vary due to usage for a long period of time. In thepresent modification example, in order to balance the fitting pressureby the upper terminal component 260 and the lower terminal component280, the gap of the initial clearance in a non-mounting state of thebattery pack is varied. That is, in a state where the battery pack 100is not mounted in the power tool main body 1 or 30 (detached state), thesmallest gap between the right and left arm portions 265 and 266 differsfrom the gap between the arm portions 285 and 286. Here, the gap betweenthe arm portions 265 and 266 of the upper terminal component 260 is setto 0.2 mm. In contrast, the smallest gap between the arm portions 285and 286 of the lower terminal component 280 is set to 0.5 mm.

In order to achieve a uniform fitting pressure, the shapes of the upperterminal component 260 and the lower terminal component 280 have alsobeen devised. That is, as illustrated in FIG. 14(2), originally in theupper terminal component 260, a substantially right-angled inner angleas indicated by the dotted line 264 b should be formed. Here, thecontour of the dotted line 264 b is extended in the direction of thearrow 264 e to realize a shape in which a reinforcement surface 264 chaving a right-angled triangular shape in a side view is added. As aresult, the contour of this inner angle part becomes oblique asindicated by the arrow 264 d, and the attachment rigidity of the armportions 265 and 266 of the upper terminal component is improved due tothis shape change. In accordance with the shape change of the innerangle part of the upper terminal component 260, the shape of the outerangle part of the lower terminal component 280 is cut off in thedirection of the arrow 284 e from a part of the dotted line 284 b toobtain a shape in which a cut-off portion 284 c having a right-angledtriangular shape in a side view is provided. As a result, the contour ofthis outer angle part becomes as indicated by the arrow 284 d, and therigidity of the arm portions 285 and 286 of the lower terminal componentis deteriorated. In the contour part indicated by the arrow 264 d andthe arrow 284 d, the contours are determined such that they aresubstantially parallel to each other in a side view and are apart fromeach other with a uniform gap therebetween. When the cut-off portion 284c is formed, the length of the bridge portion 282 in the up-downdirection becomes short. However, since the lower terminal component 280is small, the lower terminal component 280 has a sufficient strengthcompared to the upper terminal component 260. Therefore, the strengthcan be suitably balanced due to these shape changes. In this manner, inthe upper terminal component 260, the shape of the inner angle part ischanged by adding the reinforcement surface 264 c. In the lower terminalcomponent 280, the shape of the outer angle part is changed throughstrength adjustment by forming the cut-off portion 284 c. Accordingly,the strength of both can be balanced, and the fitting pressures to themain body side terminals by the arm portions 265 and 266, and 285 and286 can be substantially equivalent to each other.

FIG. 14(3) is a view of the upper terminal component 260 and the lowerterminal component 280 viewed from the front. The heights in the up-downdirection and the attachment positions of the arm portions 265 and 266,and the heights in the up-down direction and the attachment positions ofthe arm portions 285 and 286 become the same shape and the samepositional relationship as the arm portion groups of the upper terminalcomponent 200 and the lower terminal component 220 in the first exampleillustrated in FIG. 5. However, in the present modification example, thethickness of a using metal plate material differs, and they aremanufactured using a thicker plate than the terminal components in thefirst example illustrated in FIG. 5. Moreover, in a state when thebattery pack 100 is not mounted, the smallest gap differs between thearm portion sets on the upper and lower side. That is, the gap betweenthe arm portions 285 and 286 on the lower side in the right-leftdirection is configured to be larger than the gap between the armportions 265 and 266 on the upper side in the right-left direction. Thishas a relationship in which the lengths thereof are inverselyproportional to the lengths of the arm portions 265 and 266 and the armportions 285 and 286 in the mounting direction (front-rear direction)disposed vertically side by side. The long arm portions 265 and 266 faceeach other with a narrow gap therebetween in an initial state. On thecontrary, the short arm portions 285 and 286 face each other with a widegap therebetween.

As described above, in the first modification example, the upperterminal component 260 and the lower terminal component 280 having aplate thickness of 0.8 mm which is thick are used as the powerterminals. Since only a very small current flows in the signal terminalcomponent, similar to the battery pack 15 in the related art, they maybe manufactured using a metal plate having a thickness of approximately0.3 mm. In the present modification example, the rigidity of the powerterminals in which a large current flows can be further improved, andthe fitting situation can be favorably maintained not only duringworking but also over a long period of using time. In order to achievesubstantially the same fitting pressures of the arm portion sets on theupper and lower side, without being limited to only adjustment of theclearance of the fitting portions and change in shape near theattachment base, it can also be achieved by other changes, particularly,attachment of the plate thickness, selection of materials for theterminal components, and the like.

FIG. 15 is a perspective view illustrating the upper terminal component260 and a lower terminal component 280A of a second modification exampleof the present example. In the second modification example, the upperterminal component 260 is the same as that in the first modificationexample illustrated in FIG. 14. However, the lower terminal component280 differs in plate thickness and initial gap between the arm portions.That is, the plate thickness of the lower terminal component 280A isthinned to 0.6 mm from 0.8 mm of the lower terminal component 280illustrated in FIG. 14, and the gap between fitting portions 285 d and286 d is narrowed to 0.2 mm from 0.5 mm of the lower terminal component280 illustrated in FIG. 14. The gap of the fitting portions 265 d and266 d of the upper terminal component 260 is 0.2 mm, which is similar tothat in the first modification example. In this manner, the fittingpressures can be substantially equivalent to those of the fittingportions 265 d and 266 d of the upper terminal component 260 byadjusting the plate thickness and the gap between the arm portions 285and 286 having spring properties. Here, the shapes of the fittingportions 265 d and 265 d are formed to be half-cylindrical surfaces.Central axes of the cylindrical surfaces are positioned in the verticaldirection, and the wall surfaces of the fitting portions 265 d and 265 don the inner side become cylindrical surface having a radius R1 ofcurvature. The wall surfaces of the fitting portions 285 d and 286 d ofthe lower terminal component 280A on the inner side are also formed tobe cylindrical surfaces having the radius R1 of curvature. It isfavorable that the cylindrical shapes of the fitting surfaces of thefitting portions 265 d and 266 d and the fitting portions 285 d and 286d be formed at the equivalent radius R1 of curvature such that the sizesor the shapes of linear or rectangular contact parts becomesubstantially the same as each other. It is preferable that sandwichingpressures (fitting pressure) be substantially equivalent to each otherto achieve substantially the same electrical contact resistance byrealizing the uniform sizes of the contact parts and the contact regionsin this manner.

FIG. 16 is a perspective view illustrating an upper terminal component200A and the lower terminal component 220 according to a thirdmodification example of the present example. FIG. 16(1) is a viewillustrating a state where these are connected to the main body sideterminal of a rated 36 V power tool main body 30A. In the thirdmodification example, the shape of the upper terminal component 200A,particularly only the shapes of arm portions 205A and 206A differ fromthose in the first example, and the configuration of the base bodyportion of the upper terminal component 200A and the leg portions is thesame as that in the first example. The upper terminal component 200A isused as the upper positive electrode terminals 161 and 162 and the uppernegative electrode terminal 167. In the upper terminal component 200A,the positions of the fitting portions of the arm portions 205A and 206Aon the upper side are positioned on the front side of the positions ofthe fitting portions of the arm portions 225 and 226 on the lower side,such that the arm portions 205A and 206A significantly extend to thefront side. The shapes of the fitting portions facing each other arehalf-cylindrical surfaces having the equivalent radius R1 of curvature,and the shapes of the fitting portions of the arm portions 205A and 206Aand the shapes of the fitting portions of the arm portions 225 and 226are the same as each other. When the arm portions 205A and 206A arelengthened, a positive electrode terminal 72A of the 36 V side powertool main body is caused to be shorter than that in the related art inaccordance with this shape change. The size and the plate thickness of ashort bar 79 serving as a short circuit means are the same as those ofthe short bar 59 illustrated in FIG. 6. However, a semicircular cutout79 d is formed in the upper portion of a terminal portion 79 b of theshort bar 79. This cutout 79 d is provided to prevent the terminalportion 79 b from coming into contact with the arm portions 205A and206A on the upper side when the positive electrode terminal 72A and theterminal portion 79 b of the apparatus side terminal relatively move inan are shape as indicated by the arrow 45 a or in the horizontaldirection for some reason. In this manner, since the cutout 79 d isformed in the terminal portion 79 b of the short bar 79, when thebattery pack 100 is mounted and the power tool is operated, even ifrelative positional deviation occurs due to the difference betweenresonance frequencies of the power tool main body 30A and the batterypack 100, it is possible to drastically reduce a possibility ofoccurrence of a short circuit between the upper terminal component 200Aand the lower terminal component 220.

FIG. 16(2) is a view illustrating a state where the upper terminalcomponent 200A and the lower terminal component 220 are connected to themain body side terminal of the power tool main body 1 in the relatedart. When being mounted on the power tool main body 1 side of ratedvoltage of 18 V, two sets of the arm portions 205A and 206A and the armportions 225 and 226 are fitted into the positive electrode inputterminal 22. At this time, the contact positions of the fitting portionsof the arm portions 205A and 206A with respect to the positive electrodeinput terminal 22 deviate to the front side of the contact positions ofthe fitting portions of the arm portions 225 and 226 with respect to thepositive electrode input terminal 22. However, since the thickness ofthe positive electrode input terminal 22 in the vicinity thereofincluding the contact positions is uniform, if the sizes of the contactportions or the contact regions are equal to each other between that bythe arm portions 205A and 206A and that by the fitting portions of thearm portions 225 and 226, a favorable conducting state can be realized,and therefore movement of the contact position does not cause anyproblem.

FIG. 17 is a perspective view illustrating the upper terminal component200 and a lower terminal component 220A of a fourth modification exampleof the present example. FIG. 17(1) is a view illustrating a state wherethese are connected to the main body side terminal of a power tool mainbody 30B. In the fourth modification example, only the shapes of the armportions 225A and 226A of the lower terminal component 220A differ fromthose in the first example, and other configurations are the same asthose in the first example. Here, the positions of the fitting portionsof the arm portions 225A and 226A on the lower side are positioned onthe front side of the positions of the fitting portions of the armportions 205 and 206 on the upper side, such that the arm portions 225Aand 226A extend to the front side. The rear end position of the shortbar 79 is also provided on the front side of that in the related art inaccordance therewith. Moreover, a semicircular cutout 72 d is formed ina lower portion of a positive electrode terminal 72B. Regarding thiscutout 72 d, the cutout 72 d is provided to drastically reduce apossibility that the positive electrode terminal 72B may come intocontact with the arm portions 225A and 226A when the positive electrodeterminal 72B and the terminal portion 79 b of the apparatus sideterminal move as indicated by the arrow 45 b for some reason.

FIG. 17(2) is a view illustrating a state where the upper terminalcomponent 200 and the lower terminal component 220A are connected to themain body side terminal of the power tool main body 1 in the relatedart. Two sets of the arm portions 205 and 206 and the arm portions 225Aand 226A are fitted into the positive electrode input terminal 22 on thepower tool main body 1 side. Here, the positions of the contact parts ofthe arm portions 205 and 206 and the positions of the contact parts ofthe arm portions 225A and 226A are apart from each other in thefront-rear direction by a distance L. However, since the sizes of thecontact portions or the contact regions are equal to each other betweenthat by the arm portions 205 and 206 and that by the fitting portions ofthe arm portions 225A and 226A, a favorable conducting state can berealized, similar to the first example.

FIG. 18 is a perspective view illustrating a shape of the terminalportion on the power tool main body 30A side according to a fifthmodification example of the present example. In the fifth modificationexample, the positions of the positive electrode terminal and thenegative electrode terminal in the first example and the position of theshort bar are vertically inverted. Here, the upper positive electrodeterminal 162 and the upper negative electrode terminal 167 areshort-circuited by a short bar 89. Regarding the short bar 89, the samecomponent as the short bar 59 (refer to FIG. 6) in the first example canbe used, and the short bar 89 need only be cast in a synthetic resinbase of the terminal portion of the power tool main body. Theconfiguration in which a positive electrode input terminal 82 isconstituted of a terminal portion 82 a, a connection portion 82 b, and awiring terminal portion 82 c is similar to the positive electrode inputterminal 52 (refer to FIG. 6) in the first example. However, since theposition for providing the wiring terminal portion 82 c has to be on therear surface side instead of the upper surface of the terminal portion,the shapes of the connection portion 82 b and the wiring terminalportion 82 c are changed. In a similar manner, a negative electrodeinput terminal 87 is also provided with a wiring terminal portion 87 cat a different position. In accordance with the deviated positions ofthe positive electrode input terminal 82 and the negative electrodeinput terminal 87 in the terminal portion, the connection state of theupper cell unit 146 and the lower cell unit 147 is also changed. Thatis, the upper cell unit 146 is connected to the lower positive electrodeterminal 172 and the upper negative electrode terminal 167, and thelower cell unit 147 is connected to the upper positive electrodeterminal 162 and the lower negative electrode terminal 177.

As described above, even if the position for providing the short bar 89is changed, it is possible to realize the battery pack with an automaticvoltage switching mechanism of the present example. When thisconfiguration is employed, the attachment positions of the wiringterminal portions 82 c and 87 c can be drawn out to the rear sideinstead of being drawn out to the upper side of the terminal portion(refer to FIG. 7). Therefore, the degree of freedom of design of theterminal portions on the power tool main body side increases. Since theshort bar 89 has a terminal portion 89 b and a terminal portion 89 c,and the function thereof can be achieved by causing these to beshort-circuited, there is no need to connect the part of a connectionportion 89 a with a metal plate. The function may be realized by methodsin which an electrical connection relationship can be formed with aconductive member, for example, other arbitrary methods such asconnection using a lead wire and connection using a fuse element.

FIG. 19 is a circuit diagram illustrating a state where the battery pack100 of the present example is connected to the power tool main body 1 inthe related art. The power tool main body 1 in the related art isconfigured to include the positive electrode input terminal 22, thenegative electrode input terminal 27, and the LD terminal 28 on theapparatus side. The trigger switch 4 and a DC motor 5 are connected toplaces between the positive electrode input terminal 22 and the negativeelectrode input terminal 27. A switching element M101 constituted of asemiconductor is provided between the motor 5 and the negative electrodeinput terminal 27. A drain-to-source of the switching element M101 isconnected to a power supply path of the motor 5, and a gate is connectedto the positive electrode input terminal 22 via a resistor R101. Inaddition, the gate of the switching element M101 is connected to the LDterminal 28 via a resistor R102. In general, the LD terminal 28 on thebattery pack 100 side is in a high impedance state. At this time, apositive voltage is applied to the gate of the switching element M101via the resistor R101, and the switching element M101 is thus in theconducting state. At this time, if the LD terminal 168 drops to a groundpotential due to a discharging prohibition signal 341 from the batterypack 100 side, the potential of the gate of the switching element M101becomes a voltage realized by dividing the voltage of the positiveelectrode input terminal 22 using the resistors R101 and R102, and thispartial potential becomes a potential for blocking a source-to-drain ofthe switching element M101. As a result, the power supply path to themotor 5 is blocked, and therefore rotation of the motor 5 stops. Thepotential of this LD terminal 168 is switched in accordance with controlof a controller 350 on the battery pack 100 side, and switching isexecuted when in a state where the voltage of the battery cell hasdropped to a predetermined value, that is, a so-called over-dischargestate, when the current flowing in the battery cell exceeds theregulated upper limit value, when the temperature of the battery cellexceeds the upper limit value, and the like. The discharging prohibitionsignal 341 is an example of “a control signal” in the presentdisclosure, and the LD terminal 168 is an example of “a signal terminal”in the present disclosure.

As illustrated in FIG. 4, the battery pack 100 is configured to have anupper positive electrode terminal (upper positive) 162, a lower positiveelectrode terminal (lower positive) 172, an upper negative electrodeterminal (upper negative) 167, and a lower negative electrode terminal(lower negative) 177. In addition, the battery pack 100 has the LDterminal 168 as a signal terminal. In addition to those, other signalterminal groups (T terminal 164, V terminal 165, and LS terminal 166)are provided in the battery pack 100. However, illustration thereof isomitted herein. The output of the upper cell unit 146 is connected tothe upper positive electrode terminal 162 and the lower negativeelectrode terminal 177. That is, the positive electrode (positiveoutput) of the upper cell unit 146 is connected to the upper positiveelectrode terminal 162, and the negative electrode (negative output) ofthe upper cell unit 146 is connected to the lower negative electrodeterminal 177. In a similar manner, the positive electrode (positiveoutput) of the lower cell unit 147 is connected to the lower positiveelectrode terminal 172, and the negative electrode (negative output) ofthe lower cell unit 147 is connected to the upper negative electrodeterminal 167.

In each of the upper cell unit 146 and the lower cell unit 147, fivelithium ion battery cells are connected in series. A protection IC 300for monitoring the voltages of the battery cells, a protection IC 320,and the controller 350 are connected to the upper cell unit 146 and thelower cell unit 147. When both end voltages of each of the battery cellsin the upper cell unit 146 are input to the protection IC 300, theprotection IC 300 executes a cell balancing function, a cascadeconnecting function, and a disconnection detecting function, in additionto an over-charging protecting function and an over-dischargingprotecting function. The protection IC 300 is a commercially availableintegrated circuit serving as “a lithium ion battery protection IC”. Theprotection IC 300 has a built-in power source circuit for obtainingpower to operate the protection IC from the voltage of the upper cellunit 146. In addition, when the voltages of the battery cells in theupper cell unit 146 drop to be smaller than a predetermined value andare thus in an over-discharged state, a signal (high signal) 305indicating over-discharge of the protection IC 300 is output to thecontroller 350. When the voltages of the battery cells in the upper cellunit 146 have reached a predetermined value or larger at the time ofcharging and are thus in an over-charged state, a signal (high signal)306 indicating over-charge is output to the controller 350.

The protection IC 320 is connected to the lower cell unit 147. Here, thecontroller 350 is further provided in the circuit of the lower cell unit147, that is, in the circuit between the lower positive electrodeterminal 172 and the upper negative electrode terminal 167. That is, theprotection circuit provided in parallel with the upper cell unit 146 isconstituted of only the protection IC 300. In contrast, the protectioncircuit provided in parallel with the lower cell unit 147 is constitutedof the protection IC 320 and the controller 350. The controller 350includes a micro-controller unit (MCU, a so-called “microcomputer”).Outputs (over-discharge signal 305 and overcharge signal 306) from theprotection IC 300, outputs (over-discharge signal 325 and overchargesignal 326) from the protection IC 320, and a signal from a celltemperature detection means 331 are input to the controller 350. Forexample, the microcomputer of the controller 350 includes a voltagedetection circuit referred to as an analog front end (AFE) measuring avalue of a current flowing from an output voltage of a current detectioncircuit 327 to the lower cell unit 147. Driving power of the controller350 is generated by a power source circuit 321 connected to the lowercell unit 147, and a power source voltage (VDD1) is supplied to thecontroller 350. Each of the protection IC 300, the protection IC 320,and the controller 350 is an example of “a protection circuit” in thepresent disclosure. The protection circuit is directly connected to anyone of the cell units or is indirectly connected via another protectioncircuit. The protection circuit monitors the state of the battery cellsconstituting the cell units and outputs a signal corresponding to thestate of the battery cells. A circuit in which any one of the protectionIC 300, the protection IC 320, and the controller 350 is combinedbecomes an example of “a protection circuit” in the present disclosure.In addition, the protection IC 300 is an example of “a first protectioncircuit” in the present disclosure, the protection IC 320 is an exampleof “a second protection circuit” in the present disclosure, and thecontroller 350 is an example of “a controller” in the presentdisclosure. The controller is directly connected to any one of the cellunits or is indirectly connected via another protection circuit. Inaddition, the power source circuit 321 is an example of “a power sourcecircuit” in the present disclosure, and the power source voltage (VDD1)is an example of “a power source voltage” in the present disclosure.Moreover, the cell temperature detection means 331 is an example of “adetection unit” and “a temperature detection unit” in the presentdisclosure, the current detection circuit 327 is an example of “adetection unit” and “a current detection unit” in the presentdisclosure, and each of a temperature detected by the cell temperaturedetection means 331 and a current detected by the current detectioncircuit 327 is an example of “a physical quantity” in the presentdisclosure.

A shunt resistor 329 is provided on the ground side of the lower cellunit 147, but no shunt resistor is provided on the upper cell unit 146side. This is because a current value can be measured using only theshunt resistor 329 when the upper cell unit 146 and the lower cell unit147 are connected in series. Meanwhile, when the upper cell unit 146 andthe lower cell unit 147 are connected in parallel, an actual measurementcurrent value on the upper cell unit 146 side cannot be measured.However, the controller 350 may perform monitoring such that a currentvalue of the upper cell unit 146 is equivalent to the lower cell unit147. A shunt resistor and a voltage detection circuit may be configuredto be provided on the ground side of the upper cell unit 146, such thata current value on the lower cell unit 147 side is also directlymonitored by the microcomputer of the controller 350.

The controller 350 monitors a current value and a cell temperature andmonitors states of the upper cell unit 146 and the lower cell unit 147,thereby integrally controlling both operation situations. In addition,when the power tool main body 1 needs an emergency stop, the dischargingprohibition signal 341 is emitted and the potential of the LD terminal168 is changed, so that the operation on the power tool main body 1 sideis stopped via the LD terminal 28. The most important matter inmonitoring these using the controller 350 is the amperage flowing in thebattery cells included in the upper cell unit 146 and the lower cellunit 147. In recent power tools, it has become possible to extract alarge current from the battery pack 100 as the performance of batterycells is improved and the capacity is increased. However, from theviewpoint of the life-span and heat generation, it is preferable thatbattery cells be limited to a predetermined amperage (current upperlimit value or smaller). Therefore, in order to particularly monitor thecurrents flowing in the battery cells, the controller 350 monitors thecurrent value using the shunt resistor 329 and the current detectioncircuit 327 interposed in the middle of a power supply line of the lowercell unit 147.

Regarding a management protection circuit of the lower cell unit 147constituted of the protection IC 320, the controller 350, the powersource circuit 321, the current detection circuit 327, and the like, acircuit configured to be integrated in one chip as “a battery managementIC” may be used. Meanwhile, regarding the protection IC 300 for theupper cell unit 146, the same protection IC widely used in the batterypack 15 in the related art (refer to FIG. 1) can be used, such as aprotection IC commercially available as “a battery protection IC” forfive cells. The operation of the protection IC 320 is substantiallysimilar to that of the protection IC 300. When a state where thevoltages of the battery cells in the lower cell unit 147 have dropped toa predetermined lower limit value (over-discharged state) is detected,the over-discharge signal 325 is sent out to the controller 350. Inaddition, while the battery pack 100 is mounted in an external chargingdevice (not illustrated) and charging is performed, when the protectionIC 320 detects that the voltages of the battery cells have exceeded apredetermined upper limit value, the overcharge signal 326 indicating anover-charged state is sent out to the controller 350. The controller 350sends out a charging stoppage signal to the charging device (notillustrated) via the LS terminal 166 (refer to FIG. 4). As describedabove, since a battery cell protection circuit is mounted in each of theupper cell unit 146 and the lower cell unit 147, protection of thebattery through detailed battery monitoring can be realized.

In the present example, the protection circuit of the upper cell unit146 includes only the protection IC 300 and includes no microcomputer.In contrast, in addition to the protection IC 320, the controller 350including a microcomputer is provided in the protection circuit of thelower cell unit 147. Furthermore, the power source circuit 321 generatespower for operating the controller 350 using electric power of the lowercell unit 147. Since the battery pack 100 of the present example is an18 V/36 V voltage switchable type, if a microcomputer is mounted on theprotection circuit on the upper cell unit 146 side, the ground potentialof the controller 350 changes at the time of series-connection and atthe time of parallel-connection of two cell units. Meanwhile, if thepower source circuit 321 is provided on the lower stage side, the groundpotential of the power source circuit 321 does not change. Here, in thepresent example, the controller 350 having a microcomputer mountedtherein is provided in the circuit of the lower cell unit 147 instead ofthe circuit of the upper cell unit 146. Due to this disposition of amicrocomputer, the controller 350 including a microcomputer can bestably operated with an output voltage of a rated 18 V/36 V switchabletype. The ground potential of the controller 350 corresponds to “aground potential of the controller” in the present disclosure.

When the controller 350 including a microcomputer is provided in onlythe circuit on one cell unit side, a problem of imbalance in powerconsumption between two cell units occurs. Although power consumption ofthe controller 350 is extremely small, power consumption on the lowercell unit 147 side is greater than power consumption on the upper cellunit 146 side. If an imbalance state of power consumption continues fora long time, the potential on the lower cell unit 147 side becomes lowerthan the upper cell unit 146, which is not preferable. Particularly, thereason is that when the upper cell unit 146 and the lower cell unit 147are connected in parallel and a rated voltage of 18 V is output, acirculation current flows due to voltage imbalance between the cellunits immediately after the parallel-connection state. Therefore, in thepresent example, a current consumption control means 310 having afunction of adjusting the consumption current amount with respect to thelower cell unit 147 is provided in the circuit of the upper cell unit146 having less power consumption. The current consumption control means310 is interposed on one side of two cell units having less powerconsumption, that is, in parallel with the upper cell unit 146. Thecurrent consumption control means 310 is mounted in the circuit board150 (refer to FIG. 4) as a load circuit separate from the integratedprotection IC 300. The current consumption control means 310 is anexample of “a consumption current controller” in the present disclosure.

The current consumption control means 310 is controlled to be operatedin conjunction with operation of the controller 350. The microcomputerincluded in the controller 350 can switch between retention andcancellation of the power source voltage (VDD1) applied to itself andhas an ordinary operation state (normal mode) and an operation stoppagestate (so-called sleep state). While the microcomputer of the controller350 retains the power source voltage VDD1, the protection IC 300 is alsoin an operation state by switching the state of a start-up terminal 301utilized as a control signal. In the present example, the circuit of thecurrent consumption control means 310 has been devised. The currentconsumption control means 310 is configured to allow a current foradjusting power consumption to flow therein in conjunction with a statewhere the microcomputer of the controller 350 is holding the powersource voltage VDD1. Moreover, the current consumption control means 310switches the state of the start-up terminal 301. As a result, when thecontroller 350 starts up, the protection IC 300 also starts up at thesame time in conjunction therewith. Since the power source circuit 321of the controller 350 is a common circuit also serving as the protectionIC 320, when the microcomputer starts up, the protection IC 320 alsostarts up at the same time. Due to the current consumption control means310, the consumption currents consumed by a cell set (lower cell unit147) to which the controller 350 is connected and the other cell set(upper cell unit 146) become the same as each other.

The current consumption control means 310 is an electric circuitconfigured to include a plurality of switching elements M31 to M33 suchas FETs, and a plurality of resistors (resistors R31 to R35). Regardinga basic circuit configuration, the resistors R31 and R34 constitutingtwo dummy loads in series-connection are connected to a part betweenboth terminals of the upper cell unit 146, and the circuit is switchedbetween ON and OFF by the switching element M32. A source terminal ofthe switching element M32 is connected to the positive electrode of theupper cell unit 149, and a drain terminal is connected to the resistorR31. A gate terminal of the switching element M32 is connected to aconnection point between the resistors R32 and R35. One end of theresistor R32 is connected to the source terminal of the switchingelement M32, and the other end is connected to the gate terminal of theswitching element M32. One end of the resistor R35 is connected to thegate terminal of the switching element M32, and the other end isconnected to the drain terminal of the switching element M33. Theswitching element M33 inputs the power source voltage (VDD1) of themicrocomputer included in the controller 350 to a gate signal andperforms switching between ON and OFF in conjunction with the powersource voltage VDD1. The source terminal of the switching element M33 issubjected to grounding, and the resistor R33 is connected to a partbetween the source terminal and the gate terminal of the switchingelement M33. The resistor R33 is provided such that the switchingelement M33 is stably switched in accordance with a voltage change ofthe gate signal. Regarding such a current consumption control means 310,when the power source voltage VDD1 of the microcomputer is ON, the gatepotential of the switching element M33 becomes the VDD1 (high level),and when the power source voltage VDD1 is OFF, the gate potential of theswitching element M33 is 0 V (low level). The same signal as the gatesignal of the switching element M33 is also input to the protection IC320. Consequently, the switching element M33 is in an OFF state. Whenthe switching element M33 is in the OFF state, the switching element M32is also in the OFF state. Accordingly, current paths to the dummy loadside by the resistors R31 and R34 are blocked, so that power consumptionby the current consumption control means 310 is zero. In order to causethe protection IC 300 to be also OFF at the time of this state, theswitching element M31 that inputs the potential at the connection pointbetween the resistors R31 and R34 as a gate signal (operation signal302) is further provided. The drain terminal of the switching elementM31 is connected to the start-up terminal 301 of a built-in power source(not illustrated) of the protection IC 300, and the source terminal isconnected to the negative electrode of the upper cell unit 146. Theoperation signal 302 is a signal indicating an operation state of thecurrent consumption control means 310 and indicates that the currentconsumption control means 310 is operated, that is, the microcomputer ofthe controller 350 is also operated at the time of a high level.Meanwhile, when the current consumption control means 310 is notoperated, that is, when the microcomputer of the controller 350 isstopped, the operation signal 302 becomes low and the start-up terminal301 is in a high impedance state, so that the protection IC 300 isstopped.

The negative potential (reference potential A) of the upper cell unit146 becomes the ground potential at the time of parallel-connection ofthe upper cell unit 146 and the lower cell unit 147 but is equivalent tothe positive potential of the lower cell unit 147 at the time ofseries-connection. In this connection state, the potential of the uppercell unit 146 is not applied to the resistor R31 because the switchingelement M31 is OFF, so that the start-up terminal 301 is not connectedand is in a high impedance state. Meanwhile, when the switching elementM32 is ON and a current flows in the dummy load, partial voltages of theresistors R31 and R32 are applied to the gate terminal of the switchingelement M31. Therefore, the switching element M31 is ON. Consequently,the start-up terminal 301 is connected to the reference potential A.Therefore, power is supplied to the built-in power source inside theprotection IC 300, so that the protection IC 300 starts up. In aconnection form as described above, power consumed by the microcomputerof the controller 350 on the lower cell unit 147 side can also beconsumed inside the circuit of the upper cell unit 146 by the currentconsumption control means 310. Moreover, in accordance with switchingbetween movable and stoppage of the current consumption control means310, start-up and stoppage control of the protection IC 300 itself canalso be performed together. Thus, the microcomputer of the controller350 can control start-up and stoppage of the protection circuit of thelower cell unit 147 and the protection circuit of the upper cell unit146 in conjunction therewith.

The state of the microcomputer of the controller 350 includes threestages, such as a normal mode, a sleep mode, and a shut-down mode. Thenormal mode is a state where the microcomputer is starting up at alltimes. The sleep mode is a mode in which the microcomputerintermittently starts up by itself and repeats operation of stoppage for5 seconds after a start-up for 50 milliseconds. The shut-down mode is astate where the power source voltage VDD1 is not supplied at all and isa state where the microcomputer is completely stopped. The microcomputeris operated when the battery pack 100 is mounted or not mounted in thepower tool main body 1. However, when the battery pack 100 is notmounted, or when the power tool is not used for a certain period of timeor longer even if the battery pack 100 is mounted, for example, whenanother trigger operation is not performed for approximately two hoursafter a trigger operation has ended, the microcomputer is in the sleepstate. Even in this sleep state, the current consumption control means310 is operated in conjunction with a start-up of the microcomputer. Inaddition, the protection IC 300 also starts up via the currentconsumption control means 310. When the trigger switch 4 of the powertool main body 1 is pressed and a current flows in the motor 5, themicrocomputer of the controller 350 detects increase in current valuedetected by the current detection circuit 327 and returns to the normalstate.

In the present example, in the case of a configuration in which amicrocomputer is included in only one protection circuit of a pluralityof cell units, increase in potential difference between the plurality ofcell units caused by being neglected for a long period of time in astate where the battery pack is detached has been resolved by adding thecurrent consumption control means 310 performing power consumption asmuch as that in the microcomputer for the protection circuits of othercell units in which no microcomputer is provided. Therefore, balance ofa consumption current in each of the plurality of cell units can beadjusted, and thus it is possible to realize a battery pack in whichvoltage balance for every cell unit is not deteriorated even after beingstored for a long period of time.

A residual quantity display means 335 for displaying the batteryresidual quantity is provided in the battery pack 100. When the switch190 (refer to FIG. 4) for displaying the residual quantity is pressed,the battery residual quantity is displayed by the number of emittingdiodes of four light emitting diodes (not illustrated). A signal of theswitch 190 for displaying the residual quantity is input (notillustrated herein) to the controller 350, and the microcomputer of thecontroller 350 performs light-on control of the light emitting diodes ofthe residual quantity display means 335. Here, the battery residualquantity displayed by the residual quantity display means 335 may bedisplayed based on both end voltages of one cell unit of the upper cellunit 146 and the lower cell unit 147 or may be displayed based on thelowest voltage value of ten battery cells.

An output of an upper voltage detection circuit 322 connected to theupper positive electrode terminal 162 is input to the controller 350.This output indicates the potential of the upper cell unit 146 when thebattery pack 100 is not mounted in the power tool main bodies 1 and 30or an external charging device (not illustrated). Meanwhile, when thebattery pack 100 is mounted in the power tool main body 1 for a lowvoltage (18 V), since the upper positive electrode terminal 162 and thelower positive electrode terminal 172 are connected to each other, thepositive electrodes in the upper cell unit 146 and the lower cell unit147 have the same potentials, and the negative electrodes have the samepotentials. From this, the microcomputer included in the controller 350can determine whether the battery pack 100 is in a non-mounted state, ismounted in a low voltage apparatus main body, or is mounted in a highvoltage apparatus by comparing the potential of the upper positiveelectrode terminal 162 and the potential of the lower positive electrodeterminal 172. In order to detect the potential of the lower positiveelectrode terminal 172, it is preferable that the controller 350 beconfigured to be able to acquire the positive potential of a batterycell 147 a in the uppermost stage of the battery cells in the lower cellunit 147. In this manner, the microcomputer provided in the circuit ofthe lower cell unit 147 can determine whether the upper cell unit 146and the lower cell unit 147 of the battery pack 100 are in aseries-connection state (state of being mounted in a 36 V apparatus) orin a parallel-connection state (state of being mounted in an 18 Vapparatus). In this manner, the microcomputer can also monitor thevoltage value on the upper cell unit 146 side exceeding a range (voltagein the lower cell unit 147) in which the power source voltage isacquired, and therefore the microcomputer can determine the connectionstate of the voltage switchable battery pack 100 and perform optimalcontrol corresponding to the determined connection state. The uppervoltage detection circuit 322 is an example of “a detection unit” and “afirst voltage detection unit” in the present disclosure, and thepotential of the upper cell unit 146 is an example of “a physicalquantity” and “a voltage of a first cell unit” in the presentdisclosure.

The LD terminal 168 is a terminal for transmitting a signal for stoppingthe power tool main body 1 from the battery pack 100 side or a signalfor stopping an operation of an electric apparatus using a battery pack(not illustrated) as a power source. In order to change the state of theLD terminal 168, the controller 350 switches the gate signal(discharging prohibition signal 341) input to a switching element M41 ofa semiconductor from an ordinary low state (“discharging allowed” fromthe battery pack 100) to a high state (“discharging prohibited” from thebattery pack 100). For example, the switching element M41 is a P-typefield effect transistor (FET). The drain side is connected to the LDterminal 168, and the source side is subjected to grounding.Accordingly, during a normal time of the switching element M41 (when thedischarging prohibition signal 341 is low), the LD terminal 28 is in ahigh impedance state, and the potential of the LD terminal 28 issubstantially equivalent to the voltage of the positive electrode inputterminal 22 on the power tool main body 1 side. Meanwhile, when thedischarging prohibition signal 341 is switched to a high state inaccordance with control from the controller 350, the source-to-drain ofthe switching element M41 is subjected to grounding due to conduction.Therefore, the potential of the LD terminal 28 on the power tool mainbody 1 side drops to the ground potential. As a result, due todeterioration in the gate potential of the switching element M101 on thepower tool main body 1 side, that is, the partial potential caused bypartial resistors R101 and R102, the source-to-drain of the switchingelement M101 is in a non-conducting state, so that the power circuit ofthe power tool main body 1 is blocked and rotation of the motor 5 isinhibited. In this manner, since rotation of the motor 5 of the powertool main body 1 can be inhibited in response to the dischargingprohibition signal 341 emitted by the controller 350 of the battery pack100, the controller 350 can quickly stop operation of the power tool orthe electric apparatus at the time of occurrence of an event in whichpower supply from the battery pack 100 has to be halted, for example, anexcessive current at the time of discharging, deterioration in cellvoltage at the time of discharging (over-discharging), and an abnormalrise of the cell temperature (excessive temperature), so that it ispossible to protect not only the battery pack 100 but also the powertool main body 1.

FIG. 20 is a circuit diagram of the battery pack 100 of the presentexample and is a view illustrating a state where the battery pack 100 isconnected to an 18 V power tool main body 1A with a main body sidemicrocomputer. Here, the internal configuration on the battery pack 100side is completely the same as that illustrated in FIG. 19, and only theconfiguration on the power tool main body 1A side differs. Nomicrocomputer is included on the power tool main body 1 side illustratedin FIG. 19. However, in recent power tools, the use of a controller 60having a microcomputer for controlling the motor 5 has increased. Thepower tool main body 1A includes a power source circuit 61, and thecontroller 60 is operated using a uniform low voltage (reference voltageVDD2) generated by the power source circuit 61. The controller 60includes a microcomputer and monitors or controls various states insidethe power tool main body 1A using the microcomputer. A switch statedetection circuit 63 outputting a high signal or a low signal inaccordance with an output of a battery voltage detection circuit 62 anda connection state of a trigger switch 34 is connected to the controller60. In the present example, a DC motor 35 is provided in a power pathbetween the positive electrode input terminal 22 and the negativeelectrode input terminal 27, and the operation switch 34 (triggerswitch) for turning on and off the rotation of the motor 35 is providedin the circuit thereof. The switching element M101 (semiconductor) and ashunt resistor Rill are inserted between the motor 35 and the negativeelectrode input terminal 27. For example, the switching element M101 isa field effect transistor (FET), and the gate signal thereof is sent bythe controller 60. Both end voltages of the shunt resistor R111 aredetected by a current detection circuit 64, and a value thereof isoutput to the controller 60. In this circuit diagram, the motor 35 isillustrated as a DC motor with a brush. However, a configuration ofdriving a three-phase brushless motor using a known inverter circuit maybe adopted. In such a case, the rotation of the motor 35 may be stoppedby connecting the switching element M101 in series in a power path inputto an inverter circuit (not illustrated), or causing the controller 60in place of the switching element M101 to control a switching element(not illustrated) included in an inverter circuit.

The LD terminal 28 of the power tool main body 1A is connected to thecontroller 60 via a resistor R112. Moreover, the reference voltage VDD2is connected to the controller 60 side of the resistor R112 via aresistor R113. Therefore, when the LD terminal 28 is in a high impedancestate, a voltage close to VDD2 is applied to an input line 65 of thecontroller 60, and when the LD terminal 28 drops to the groundpotential, the partial voltages of the resistors R113 and R112, that is,a voltage drastically lower than the reference voltage VDD2 istransmitted to an input port of the controller 60 through the input line65. The controller 60 detects a change in the potential of this inputline 65, controls the gate signal of the switching element M101, andcontrols allowance or stoppage of power supply to the motor 35.

In this manner, on the power tool main body 1A side, a circuit forstopping the motor 35 is provided in accordance with a dischargingprohibition signal input via the LD terminals 168 and 28. However, whenthe controller 60 is provided on the power tool main body 1A side,instead of a configuration in which the controller 350 on the batterypack 100 side monitors an overcurrent and stops the motor 5 on the powertool main body 1A side, it is preferable that the controller 60 on thepower tool main body 1A side directly monitor an overcurrent using thecurrent detection circuit 64. When the controller 350 on the batterypack 100 side monitors an overcurrent, an average control condition(threshold value for an overcurrent) that can be applied to a pluralityof power tool main bodies has to be set. However, when the controller 60on the power tool main body 1A side monitors an overcurrent, an optimalcontrol condition (high threshold value for an overcurrent) can be setfor the power tool main body 1A. Therefore, the controller 350 can avoidoutput limitation of the power tool due to the set average controlcondition (low threshold value for an overcurrent). Avoidance of thisoutput limitation is particularly effective for new power tools to bereleased in the future, and it is possible to realize control in whichcapability of a new power tool main body 1A is maximized.

In the present example, the controller 350 on the battery pack 100 sidedetermines whether or not the controller 60 having a microcomputer isincluded on the power tool main body 1 or 1A side where the battery pack100 is mounted and changes a condition for overload protection on thebattery pack 100 side in accordance with a determination result.Specifically, as in FIG. 19, when no microcomputer is included on thepower tool main body 1 side, an overcurrent limit value at the time of alow voltage output is set to a threshold value for the power tool mainbody 1A with no microcomputer, for example, 20 A (default value). Arange of this default value may be suitably set in accordance with thecapacity or the performance of battery cells to be used. Since thisovercurrent limit value is equivalent to a value set for the batterypack 15 in the related art, the power tool main body 1A with nomicrocomputer in the related art can be driven using the battery pack100 of the present example. Meanwhile, when a microcomputer is includedon the power tool main body 1A side, the overcurrent limit value at thetime of a low voltage output is not set for the battery pack 100 side,and the microcomputer of the controller 60 on the power tool main body1A side takes charge of monitoring an overcurrent value. As a result,the controller 60 can monitor an optimal current along thecharacteristics of the using motor 5 or the configurationcharacteristics of the power tool main body 1A and the like, andtherefore it is possible to avoid a problem that the capability of thepower tool main body 1A may not be able to be effectively exhibited dueto excessively limited the overcurrent limit value on the battery pack100 side. In addition, the power tool main body 1A can maximize thecapability of the battery pack 100, and thus a high-output power toolcan be realized. In this manner, changing the condition for overloadprotection on the battery pack 100 side between the low voltage side anda high voltage side denotes that the controller 60 on the power toolmain body side can perform overload protection that is optimal for thepower tool main body 1A while there is still room for a higher outputand further improvement in low voltage power tool main bodies to benewly released in the future.

In order to determine whether or not the controller 60 having amicrocomputer is included on the power tool main body 1 or 1A side, anLD terminal voltage detection circuit 328 for detecting a value of avoltage applied to the LD terminal 28 is newly provided inside thebattery pack 100. The LD terminal voltage detection circuit 328 isconnected to the LD terminal 168 through a connection line 342, and theLD terminal voltage detection circuit 328 outputs an outputcorresponding to a terminal voltage to the controller 350. Themicrocomputer included in the controller 350 determines whether or notthe controller 60 including a microcomputer is present on the power toolmain body side by measuring the LD terminal voltage after the batterypack 100 is mounted and while the discharging prohibition signal 341 isnot emitted. In a case of the power tool main body 1 having nomicrocomputer, as it can be seen from the circuit diagram in FIG. 19,the power tool main body 1 is in a state where a voltage substantiallyequivalent to that of the positive electrode input terminal 22 isapplied to the LD terminal 28. Since the microcomputer of the controller350 detects a voltage of the upper positive electrode terminal 162 usingthe upper voltage detection circuit 322, the microcomputer can determinewhether or not a microcomputer is included in the power tool main body 1by comparing the voltage of the upper positive electrode terminal 162and the LD terminal voltage. Meanwhile, as it can be seen from thecircuit diagram in FIG. 20, in a case of the power tool main body 1Ahaving a microcomputer, a voltage substantially equivalent to thereference voltage VDD2 (for example, 5 V or 3.3 V) for driving amicrocomputer is applied to the LD terminal 28. Thus, the microcomputerof the controller 350 can easily determine that a microcomputer isincluded in the power tool main body 1A by only detecting the LDterminal voltage without comparing it with the voltage of the upperpositive electrode terminal 162 using the upper voltage detectioncircuit 322. As described above, since the connection line 342 and theLD terminal voltage detection circuit 328 are provided in the batterypack 100, the controller 350 can easily determine whether a tool is anelectronic control supporting tool including a low voltage-drivencontroller such as a microcomputer on the power tool main body or theelectric apparatus main body side, or a non-supporting tool. Inaddition, the controller 350 can change a control parameter, forexample, the overload protection condition for monitoring the batterycells in accordance with determination results. Here, the value for thecontrol parameter to be changed may be stored in advance in anon-volatile memory included in the microcomputer, such that any storedvalue is read out and set in accordance with the determination results.The LD terminal voltage detection circuit 328 is an example of “adetection unit” and “a second voltage detection unit” in the presentdisclosure, and the voltage of the LD terminal 168 is an example of “aphysical quantity” in the present disclosure.

FIG. 21 is a circuit diagram of a state where the battery pack 100 ismounted in the power tool main body 30 that can support a high load.Regarding a feature point of the power tool main body 30 that cansupport a high load, the power tool main body 30 has terminals (positiveelectrode input terminal 52, negative electrode input terminal 57, andterminal portions 59 b and 59 c of short bar) on the apparatus siderespectively corresponding to the positive electrode terminals (162 and172) and the negative electrode terminals (167 and 177) of the batterypack 100. The short bar 59 is a metal component having the terminalportion 59 b on one side and having the terminal portion 59 c on theother side. When the battery pack 100 is mounted on the power tool mainbody 30 side, the lower positive electrode terminal 172 and the lowernegative electrode terminal 177 is short-circuited due to the short bar59. In addition, the positive electrode input terminal 52 of the powertool main body 30 is connected to the upper positive electrode terminal162, and the negative electrode input terminal 57 is connected to theupper negative electrode terminal 167. In this manner, an output of theupper cell unit 146 and the lower cell unit 147 in series-connection,that is, a rated voltage of 36 V can be obtained using the shapes of twodivided main body side terminals. The configuration on the power toolmain body 30 side is substantially the same as the internalconfiguration of the power tool main body 1A illustrated in FIG. 20. Amotor 45 is a rated 36 V motor. However, similar to the motor 35illustrated in FIG. 20, a brushless DC motor may be driven using aninverter circuit. The switching element M101 is provided in series withthe power circuit for the motor 45. The ON and OFF state of theswitching element M101 is controlled based on the gate signal outputfrom the controller 60. Rotation of the motor 45 is stopped by turningoff the switching element M101. In the high voltage power tool main body30 as well, the procedure of sending out the discharging prohibitionsignal 341 from the battery pack 100 side is completely the same asthose of the circuits illustrated in FIG. 19 and FIG. 20. That is, whenthe controller 350 on the battery pack 100 side is controlled, thesource-to-drain of the switching element M41 is conducted, and when theLD terminal 168 drops to the ground potential, the state is transmittedto the input port of the microcomputer included in the controller 60.Therefore, the controller 60 can detect the state as a dischargingprohibition signal from the battery pack 100 side. However, in the 36 Vpower tool main body 30, discharge prohibited control due to anovercurrent is configured to be performed by the controller 60 on thetool main body side, such that the battery pack 100 side is not involvedin monitoring related to an overcurrent, or the threshold value forstoppage due to an overcurrent is sufficiently raised to a value closeto the limit value for the battery cells so that the microcomputer ofthe controller 350 does not have to be practically involved inmonitoring the current value. As a result, it is possible to achieveboth a higher output of the battery pack 100 and maintenance ofcompatibility with the battery pack 15 in the related art.

Next, a procedure in which the controller 350 of the battery pack 100outputs a discharging prohibition signal will be described using FIG.22. A series of procedures illustrated in FIG. 22 can be executed withsoftware by a microcomputer using a program stored in the controller 350in advance and can be automatically executed when the battery pack 100starts up. First, the microcomputer determines whether the upper cellunit 146 and the lower cell unit 147 of the battery pack 100 are inparallel-connection or in series-connection by determining whether theconnected power tool main body is a low voltage (18 V) apparatus or ahigh voltage (36 V) apparatus (Step 371). In a case ofseries-connection, a parameter for series-connection is set as a controlparameter of the controller 350 (Step 372). In addition, in a case ofparallel-connection, a control parameter for parallel-connection is set(Step 373). Here, regarding the control parameter, for example, it isconceivable to adopt a current limit value I_(max), a cell voltage upperlimit value V_(max) during charging, a cell voltage lower limit valueV_(min) during discharging, an upper limit value T_(max) for the celltemperature, and the like. Here, the current limit value I_(max) duringdischarging at the time of parallel-connection is set to 20 A, and thecurrent limit value I_(max) during discharging at the time ofseries-connection is not set (no limit value) or is set to a drasticallylarger value (for example, within a range of approximately 40 to 80 A)than that at the time of parallel-connection. The upper limit valueT_(max) for the cell temperature during discharging is 80° C. regardlesswhether the connection state is series-connection orparallel-connection. The cell voltage lower limit value V_(min) duringdischarging is 2.5 V/cell regardless whether the connection state isseries-connection or parallel-connection.

Next, the microcomputer determines whether a battery cell having thecell voltage lower limit value V_(min) (predetermined value) or smalleris present based on monitoring results of the voltages of the batterycells included in the lower cell unit 147 (Step 374). Here, when thecell voltage lower limit value V_(min) or smaller is present in anybattery cell, the process proceeds to Step 378. When all cell voltagesare larger than the cell voltage lower limit value V_(min), themicrocomputer subsequently determines whether or not the over-dischargesignal 305 from the protection IC 300 side is high (Step 375). Thepresence of a high over-discharge signal denotes that any battery cellin the upper cell unit 146 has the cell voltage lower limit valueV_(min) or smaller. Therefore, in such a case, the process proceeds toStep 378. In a case of No in Step 375, the microcomputer determineswhether or not a peak current value detected by the current detectioncircuit 327 is a predetermined threshold value I₁ or larger (Step 376).Here, a peak current value I may be detected by simply monitoring amomentary value of a peak current, or an influence of a currentprotruding in a spire-shaped may be excluded by detecting an averagecurrent within time windows that have been divided to a certain extent.In a state where the upper cell unit 146 and the lower cell unit 147 areconnected in series, and when the cell current limit value I_(max) isnot set, the process skips Step 376 and proceeds to Step 377.

Next, the microcomputer determines whether the battery temperaturedetected by the cell temperature detection means 331 is a predeterminedthreshold value Ti or larger (Step 377). Here, thermistors TH1 and TH2are provided in both the upper cell unit 146 and the lower cell unit 147and temperatures are measured. When any temperature becomes thethreshold value Ti or larger, the process proceeds to Step 378. Whenboth temperatures are smaller than the threshold value Ti in Step 377,the process returns to Step 371. When both temperatures become thethreshold value Ti or larger, the microcomputer of the controller 350sends out the discharging prohibition signal 341 to stop the motors 5,35, and 45 of the power tool main bodies 1, 1A, and 30 and turns on theswitching element M41 such that the LD terminal 168 drops to the groundpotential. Thereafter, the process returns to Step 371 (Step 378). Thecontroller 350 can monitor the state of the battery cell, and asnecessary, the controller 350 can stop an operation state of the powertool or the electric apparatus in which the battery pack 100 is mountedusing the discharging prohibition signal 341, by repeating the foregoingprocedure.

Next, a specific circuit configuration of the residual quantity displaymeans 335 and the upper voltage detection circuit 322 of the batterypack 100 will be described using FIG. 23. FIG. 23 illustrates aconfiguration of the residual quantity display means 335 and aconfiguration part of the upper voltage detection circuit 322 in detail,and other configurations on the battery pack 100 side are the same asthose of the battery pack 100 in FIG. 19 to FIG. 21. The microcomputerof the controller 350 has an input output port group 353, and four inputoutput port thereof are connected to light emitting diodes LD0 to LD3inside the residual quantity display means 335. In addition, switchingelements M0 are provided between the power source voltage VDD1 and eachof the light emitting diodes LD0 to LD3 inside the residual quantitydisplay means 335. One input output port IO0 of four input output portsIO0 to IO3 is connected to the gate. In addition, the gate terminal ofthe switching element M3 is connected to another input output port (IO3)of the four input output ports. The switching element M3 is used forcontrolling connection or blockage of the source-to-drain of a switchingelement M4.

Regarding a basic configuration, the upper voltage detection circuit 322is constituted of resistors R6 and R7, and intermediate potentialsthereof are input to an input port AN0 of the controller 350 as avoltage (detection of upper potential voltage) of the upper cell unit146. The switching element M4 constituted of an FET is interposedbetween the resistor R6 and the upper positive electrode terminal 162.The gate terminal of the switching element M4 is connected to the drainterminal of the switching element M3 controlled to be turned on and offthrough the input output port IO3. That is, when the light emittingdiode LD3 is turned off, if the input output port IO3 is OFF, theswitching element M3 is OFF. Accordingly, the gate potential of theswitching element M4 remains high, so that the source-to-drain of theswitching element M4 is conducted (ON) and detection of an upperpotential voltage is input to the input port AN0 of the microcomputer.An input port group 352 (AN0, AN1, and the like) has an A/D convertingfunction of converting an input analog signal into a digital signal.Meanwhile, when IO3 is increased in order to turn on the light emittingdiode LD3, the switching element M3 is in an ON state, so that the gateterminal of the switching element M4 drops to the ground potential.Therefore, the source-to-drain of the switching element M4 is blocked(OFF). In such connection, the controller 350 can detect a voltage ofthe upper positive electrode terminal 162 using the input port AN0.

As described above, the controller 350 needs three ports AN1 and AN2 intotal including two input ports for inputting an output of the celltemperature detection means 331 in addition to the input port AN0 forinputting a voltage of the upper positive electrode terminal 162. Thecell temperature detection means 331 includes two thermistors includingthe thermistor TH1 measuring the temperature of the upper cell unit 146and the thermistor TH2 measuring the temperature of the lower cell unit147. However, preparing a microcomputer having three input ports AN0 toAN2 for inputting three items including a voltage of the upper positiveelectrode terminal 162, an output of the thermistor TH1, and an outputof the thermistor TH2 leads to increase in cost of the microcomputer andincrease in size of the chips. Here, FIG. 24 illustrates a configurationthat is devised to cause these three inputs to share one input port AN0.

FIG. 24 is an input/output circuit diagram of a microcomputer 351 insidethe controller 350. In FIG. 24, the microcomputer 351 has the input portgroup 352 and the input output port group 353. The input port group 352has a function of converting an input analog signal into a digitalsignal, and one input port AN1 thereof is connected for inputting asignal from the thermistors TH1 and TH2 and an upper voltage detectioncircuit 322A. The input output port group 353 is an input output portserving as both an input port and an output port. Here, four inputoutput ports IO0 to IO3 are connected to the light emitting diodes (LD0to LD3), respectively. The switching element M0 for controlling ON/OFFof supplying power (VDD1) to the light emitting diode LD0 to LD4 isconnected to the input output port IO0. A resistor R5 is connected tothe gate-to-source of the switching element M0, and the switchingelement M0 and the resistor R5 constitute a switching means 364controlling ON and OFF of the light emitting diode LD0 to LD4. The inputoutput ports IO1 to IO3 are connected to the light emitting diodes LD1to LD3 and are connected to the gate terminals of the switching elementsM1 to M3, respectively.

In two thermistors TH1 and TH2, one terminal is connected to thereference voltage VDD1 of the microcomputer 351 via a common resistor Raand the other terminal is connected to the ground via the switchingelements M1 and M2. For example, the thermistors TH1 and TH2 are NTCthermistors having characteristics in which the resistance value fallswhen the temperature rises. The thermistors TH1 and TH2 are disposed inthe vicinity of the battery cells such that the microcomputer 351measures the temperatures of the battery cells. Here, it is favorablethat the thermistor TH1 be disposed in the vicinity of the upper cellunit 146 and the thermistor TH2 be disposed in the vicinity of the lowercell unit 147. The switching elements M1 to M3 are semiconductorswitches that can electrically switch between ON and OFF. The drainterminal of the switching elements M1 and M2 is connected to the otherterminal of TH1 and TH2, and the source terminal is connected to theground. The drain terminal of the switching element M3 is connected tothe upper voltage detection circuit 322A via a resistor Rb, and thesource terminal is connected to the ground. The gate terminals of theseswitching elements M1 to M3 are respectively connected to the inputoutput ports IO1 to IO3 of the microcomputer 351, and the sourceterminal is subjected to grounding. The grounding resistors R6 to R8 forcausing the gate-to-source to be 0 V when the input output ports IO1 toIO3 are opened are provided between the gate terminal and the sourceterminal of the switching elements M1 to M3, respectively.

Regarding four light emitting diodes LD0 to LD4, diodes having anarbitrary color can be used. Here, green or red diodes are used. In thecircuits of the light emitting diodes LD0 to LD4, the resistors R0 to R3for limiting a current are connected in series. The resistors R0 to R3having the same resistance value can be used. Here, in the input outputport IO0, connection to the gate terminal and connection to the lightemitting diode LD0 of the switching element M0 are performed in common.In this manner, the input output port IO0 can be set to either high orlow by connecting the switching element M0 and the light emitting diodeLD0 to the input output port IO0 in parallel-connection, and a circuitsurrounded by the dotted line can be utilized as the switching means 364for switching between turning on or not turning on all the lightemitting diodes LD0 to LD3. When turning on other light emitting diodesLD1 to LD3, they can be turned on by causing the output of the inputoutput ports IO1 to IO03 to be lower (ground potential) in a state wherethe light emitting diode LD0 is turned on.

In the input output ports IO1 to IO03, when the light emitting diodesLD0 to LD3 are turned off, any one signal of the thermistors TH1 and TH2and the upper voltage detection circuit 322A is selected and is input tothe input port AN1. That is, any one output of the input output portsIO1 to IO3 is switched to be high while the input output port IO0 islow, so that the outputs of the thermistors TH1 and TH2 and the uppervoltage detection circuit 322A can be selectively input to the inputport AN1. In addition, even when any of the light emitting diodes LD0 toLD3 is turned on, if the signal of the input output port IO0 is in ahigh impedance state for a period during which the microcomputer 351acquires the outputs of the thermistors TH1 and TH2 and the uppervoltage detection circuit 322A, these outputs can be sequentially inputto the input port AN1 in time series. When the outputs are input to thisinput port AN1, all the light emitting diodes LD0 to LD3 are in an OFFstate. However, while being turned off, temperature detection isperformed by the thermistors TH1 and TH2, or voltage detection isperformed by the upper voltage detection circuit 322A, and then thelight emitting diodes LD0 to LD3 return to the ON state again. That is,a procedure is repeated as follows: the light emitting diode is turnedoff→detection is performed by the thermistor TH1→the light emittingdiode is turned off after being turned on again for a certain period oftime→detection is performed by the thermistor TH2→the light emittingdiode is turned off after being turned on again for a certain period oftime→voltage detection is performed by the upper voltage detectioncircuit 322A→the light emitting diode is turned on again. The timerequired for temperature detection performed by the thermistors TH1 andTH2 and voltage detection performed by the upper voltage detectioncircuit 322A is 1 millisecond, for example. If these steps of detectionare performed sequentially at intervals of 50 milliseconds, an ON timeof 49 milliseconds is present after the OFF time of 1 millisecond.Therefore, three steps of detection including temperature detectionperformed by the thermistors TH1 and TH2 and voltage detection performedby the upper voltage detection circuit 322A can be completed during 150milliseconds. At this time, if any of the light emitting diodes LD0 toLD3 is turned on, an OFF state of the light emitting diode of 1millisecond is included for every 50 milliseconds. However, human eyesfeel such an interval of an OFF state the same as a continuous ON state,a temporary OFF state is not a problem.

FIG. 25 is a table showing a corresponding relationship between theinput output ports IO0 to IO3 and an output state of each of outputapparatuses in FIG. 24. The vertical axis indicates an ON state of thelight emitting diode (LED), detection performed by the thermistors TH1and TH2, and the voltage detection state of the upper voltage detectioncircuit 322A. Signal levels of the input output port group 353 at thetime of detection are indicated in fields 353 a and 353 b. Here, forexample, when the battery capacity is within a range of 25 to 50%, onlythe light emitting diode LD0 is turned on. When the battery capacity iswithin a range of 50% to 75%, two light emitting diodes LD0 and LD1 areturned on. When the battery capacity is within a range of 75% to smallerthan 100%, three light emitting diodes LD0 to LD2 are turned on. In acase of a fully charged state, four light emitting diodes LD0 to LD3 areturned on. First, control of turning on the light emitting diodes LD0 toLD3 will be described. In order to turn on only the light emitting diodeLD0 (LD0: ON), only the input output port IO0 is caused to be low(ground potential) as indicated in the second line of the field 353 a,and IO1 to 103 are caused to be in a high impedance state. In order toturn on two lights, that is, the light emitting diodes LD0 and LD1 (LD0and LD1: ON), the input output ports IO0 and IO1 are caused to be low asindicated in the third line of the field 353 a, and 102 and 103 arecaused to be in a high impedance state. In order to turn on threelights, that is, the light emitting diodes LD0 to LD2 (LD0, LD1, andLD2: ON), the input output ports IO0 to IO2 are caused to be low asindicated in the third line of the field 353 a, and only 103 is causedto be in a high impedance state. In order to turn on all the lightemitting diodes LD0 to LD4 (LD0, LD1, LD2, and LD3: ON), all the inputoutput ports IO0 to IO3 are caused to be low as indicated in the fifthline of the field 353 a. Through such control, the residual quantity ofthe battery voltage can be displayed by turning on the light emittingdiodes LD0 to LD3. When the input output port IO0 is in a high impedancestate as indicated in the field 353 a, all the light emitting diodes LD0to LD3 can be turned off.

When temperature detection is performed by the thermistors TH1 and TH2,as indicated in the field 353 b, the input output port IO0 of the inputoutput port group 353 need only be high, and any one correspondingsignal level of the thermistors TH1 and TH2 need only be high (VDD1potential). For example, when detection is performed by the thermistorTH1, if IO1 is turned on (high), the switching element M1 is turned on,and a predetermined voltage is applied to both ends of the thermistorTH1, so that the microcomputer 351 can detect the voltage value of thethermistor TH1 from the input port AN1. When detection is performed bythe thermistor TH2, if IO2 is turned on (high), the switching element M2is turned on, and the microcomputer 351 can detect the voltage value ofthe thermistor TH2 from the input port AN1. When voltage detection isperformed by the upper voltage detection circuit 322A, if the inputoutput port IO0 is caused to be high and IO3 is turned on (high), theswitching element M3 is turned on, and the microcomputer 351 can detectthe voltage value of the upper voltage detection circuit 322A (uppercell unit 146) from the input port AN1. At this time, the input outputports IO1 and 102 need to be low. In this manner, the signal of IO0remains in a high state in any case, and the signal levels of IO1 to IO3are sequentially switched from a low state to a high state. Even if theinput output port IO0 is caused to be in a high impedance state, thatis, a turned off state instead of a high state, temperature detectionperformed by the thermistors TH1 and TH2 and voltage detection performedby the upper voltage detection circuit 322A can be selectivelyperformed. As described above, since a plurality of input signals areinput to the input port AN1 in a switching manner using signals of theinput output ports IO1 to IO3, only one input port AN1 can be required,and the number of input ports can be reduced.

Example 2

FIG. 26 is a circuit diagram of a battery pack 100A according to asecond example of the present disclosure and is a view illustrating astate where the battery pack 100A is connected to the power tool mainbody 1 in the related art. The battery pack 100A has a rated voltage of18 V, which cannot be switched. The controller including themicrocomputer described in FIG. 19 to FIG. 21 is applied to thevoltage-fixed battery pack 100A instead of the voltage switchablebattery pack 100. In FIG. 26, the power tool main body 1 indicated onthe left side is completely the same as the power tool main body 1illustrated in FIG. 19. The battery pack 100A has a form in which theupper cell unit 146 and the protection circuit (protection IC 300) thatbelongs thereto, the current consumption control means 310, the lowerpositive electrode terminal 172, and the lower negative electrodeterminal 177 are removed from the battery pack 100 illustrated in FIG.19. Here, the same reference sign numbers are applied to the sameelements and the same circuits. A cell unit 148 is substantially thesame as the lower cell unit 147. However, the upper side and the lowerside are not distinguished from each other, and the shape of a separator(not illustrated) holding the battery cells changes. Accordingly,reference signs having different numbers are applied thereto. In thebattery pack 15 in the related art, the cell unit 148 is monitored byonly the protection IC 320 without providing the controller 350illustrated in FIG. 26. However, in the present example, the controller350 having a microcomputer is added by adding the protection IC 320 tothe inside of the protection circuit of the battery cell. In thismanner, since a protection circuit provided with a microcomputer isemployed, on the battery pack 100A side, it is possible to determinewhether or not the power tool main body side includes a microcomputer,so that control of the microcomputer on the battery pack 100A side canbe changed depending on the presence or absence thereof.

When the battery pack 100A is mounted in the power tool main body 1 andthe trigger switch 34 is pushed to be in state where a current flows,the controller 350 returns to the normal mode from the start-up or thesleep state. When starting up to this normal mode, the battery pack 100Ameasures the voltage of the LD terminal 168 using the LD terminalvoltage detection circuit 328. Through this measurement, the controller350 can detect whether or not the power tool main body 1 includes amicrocomputer. When there is a microcomputer, the control parameter ischanged. In the example of FIG. 26, the controller 350 determines thatthe power tool main body 1 has “no microcomputer”. Therefore, thecontrol parameter remains to be set for a power tool having nomicrocomputer, that is, a default value. Similar to that indicated inthe first example, this control parameter includes an overcurrentthreshold value, an over-discharging voltage value, an upper limit valuefor the battery cell temperature, and the like.

A current flowing in the cell unit 148 is measured by the microcomputerincluded in the controller 350 by monitoring both end voltages of theshunt resistor 329 using the current detection circuit 327. As a resultof this measurement, when the control parameter for monitoring a currentexceeds the overcurrent threshold value, the microcomputer of thecontroller 350 sets the discharging prohibition signal 341 to be high,such that rotation of the motor 35 is stopped. In this manner, since thecurrent value is monitored by the microcomputer of the controller 350instead of the protection IC 320, it is possible to perform variouscontrol using the microcomputer.

FIG. 27 is a circuit diagram of the battery pack 100A according to thesecond example of the present disclosure and is a view illustrating astate where the battery pack 100A is connected to the 18 V power toolmain body 1A with a microcomputer. In this diagram, the power tool mainbody 1A illustrated on the left side is completely the same as thatillustrated in FIG. 20. In addition, the battery pack 100A illustratedon the right side is completely the same as that illustrated in FIG. 26.Switching of the condition for overload protection in the controller 350is mainly the current limit value during discharging. When the batterypack 100A is mounted in the power tool main body 1 in the related arthaving no microcomputer, the controller 350 limits the current limitvalue I_(max) to approximately 20 A. However, when the power tool mainbody 1A includes a microcomputer, the current of the power tool mainbody is monitored by the main body side microcomputer. Therefore, thereis no need to provide the current limit value I_(max) set in thecontroller 350. Thus, the controller 350 is not provided with thecurrent limit value I_(max) or is set to have a current upper limitvalue (for example, 60 A) that can be drawn out from the cell unit 148.The current upper limit value that can be drawn out is not determinedbased on the restriction on the power tool main body 1A side but dependson the performance of the battery cell. In this manner, on the batterypack 100A side, since there is no need to limit the capability of thebattery pack more than necessary any longer, while supporting thebattery packs that can draw out larger current in accordance withimprovement in performance of battery cells, the power tool main body 1Aside can draw out the capability thereof as much as possible.Furthermore, since current limitation similar to that in the related artis also performed with respect to the power tool main body 1 in therelated art, it is possible to realize the battery pack 100A having highcompatibility and high reliability. In the second example, switching thecondition for overload protection may be realized by changing the celltemperature detection value, the over-discharging voltage value, and thelike without being limited to only the peak current value and theaverage current value. In addition, overload protection corresponding tocomputation results may be performed by providing a threshold value forall of these values such that not only overload protection is performedsimply by determining whether or not the value has exceeded thethreshold value but also utilizing that the controller 350 includes amicrocomputer, and by performing computation using these parameters. Inthis manner, when a computing expression is used, for example, it ispossible to perform control in which the threshold value for theover-discharging voltage is increased when the cell temperature is highand the threshold value for the over-discharging voltage is decreasedwhen the cell temperature is high by performing control such that theover-discharging voltage changes between when the cell voltage is highand low. As a result of monitoring of the controller 350, when the powertool needs to be stopped, the discharging prohibition signal 341 is sentout to the switching element M41 from the controller 350, and thesource-to-drain of the switching element M41 is conducted. Therefore,the LD terminal 28 on the power tool main body 1A side is in a lowlevel, and rotation of the motor 5 is stopped.

Example 3

FIG. 28 is a perspective view illustrating a battery pack 400 of a thirdexample of the present disclosure. A plurality of connection terminalsthat are interlocked with terminals of a charging device or a tool mainbody to be electrically conducted are provided in the battery pack 400.Each of the connection terminals provided herein is constituted of twoconnection terminal components separated from each other in the up-downdirection and has a feature in the shapes of the connection terminalcomponents. The appearance shape of the battery pack 400 issubstantially the same as the battery pack 100 illustrated in the firstexample. The only difference in appearance is that a stepped portion(refer to 115 a and 115 b in FIG. 12) partially raised on an upper stagesurface 415 of an upper casing 410 is not formed, and a depressionportion (refer to 111 a in FIG. 12) is not formed in the corner portionon the left front side of a lower stage surface 411. A plurality ofslots 420 are disposed in a stepped portion at a connection part betweenthe upper stage surface 415 and the lower stage surface 111. However,the width and the size of the slot 420 are substantially equivalent tothose of the battery pack 100 in the first example. A raised portion 432is formed on the rear side on the upper stage surface, and a latch 441is provided on both right and left sides of the raised portion 432.

Ten battery cells 446 are accommodated inside a lower casing 401. Here,the upper cell unit and the lower cell unit having five battery cells inseries-connection are provided, and a rated voltage of 18 V that is anoutput of the cell units in parallel-connection is output. That is, thebattery pack 400 is a voltage-fixed type. Each of the connectionterminals constitutes one terminal with two terminal components such asone terminal component on the upper side and another terminal componenton the lower side. That is, the charging positive electrode terminal isconstituted of an upper positive electrode terminal 461 and a lowerpositive electrode terminal 471, and these are short-circuited. Thedischarging positive electrode terminal is constituted of an upperpositive electrode terminal 462 and a lower positive electrode terminal472, and these are short-circuited. The set of the upper positiveelectrode terminal 461 and the lower positive electrode terminal 471,and between the upper positive electrode terminal 462 and the lowerpositive electrode terminal 472, a self-controlled protector (notillustrated) is connected therebetween.

The negative electrode terminal is constituted of an upper negativeelectrode terminal 467 and a lower negative electrode terminal 477, andthese are connected to each other. In this manner, since one connectionterminal is configured to be divided into two connection terminalcomponents, the number of contact parts and the total area with respectto the apparatus side terminal on the power tool main body 1 sideincrease. Therefore, a problem such as heat generation due to a contactfailure easily caused by vibration when the power tool is operated isunlikely to occur, so that the power tool can be stably used for a longperiod of time and the long-life battery pack 400 can be realized.

In the connection terminals, the signal terminals for transmitting asignal, that is, each of a T terminal set (upper T terminal 464 andlower T terminal 474), a V terminal set (upper V terminal 465 and lowerV terminal 475), an LS terminal group (upper LS terminal 466 and lowerLS terminal 476), and an LD terminal group (upper LD terminal 468 andlower LD terminal 478) is also constituted of two terminals, and upperand lower terminals are connected to each other and have the samepotentials. The upper connection terminals (461 to 462 and 464 to 468)and the lower connection terminals (471 to 472 and 474 to 478) are fixedto a circuit board 450. A battery cell protection IC is mounted in thiscircuit board 450, but a microcomputer or light emitting diodes fordisplaying a battery residual quantity is not provided.

FIG. 29 is an enlarged view of a part of the connection terminal in FIG.28. Both the upper terminal components (465 to 468) and the lowerterminal components (476 to 478) have a substantially L-shape in a sideview. The leg portions of the upper and lower terminal components arefixed to the circuit board 450 side by side in the mounting direction.This fixing method is a method similar to that in the first exampleillustrated in FIG. 4 and FIG. 5. The leg portions penetrate theattachment holes of the circuit board 450, and soldering is performedfrom the rear side of the circuit board 450. In each of the upperterminal components (465 to 468) and the lower terminal components (476to 478), a fitting portion 478 c bent into a substantially V-shape suchthat a part of a gap between the arm portions on both sides becomesnarrow is formed. In the fitting portions in the battery pack in therelated art, a substantially V-shaped mountain part is disposed to beorthogonal to the insertion direction of the apparatus side terminal.That is, in the terminal components in the related art, a ridgeline of asubstantially V-shaped mountain part (for example, an apex part on theinner surface side of a part indicated in the fitting portion 478 c) isconfigured to vertically extend. However, in the present example, theextending direction of the ridgeline is obliquely formed instead of theup-down direction. Therefore, the length of a contact part of theplate-shaped main body side terminal and the terminal component withrespect to the fitting portion can be increased.

FIG. 30(1) is a perspective view illustrating an upper terminalcomponent 480. However, illustration of the leg portions of the upperterminal component 480 is omitted, and only a part positioned on theupper side of the circuit board 450 is illustrated. The upper terminalcomponent 480 is realized by cutting out a flat plate formed of aconductive metal through pressing, bending the cut plate into a U-shapethereafter, and forming a predetermined bent shape in arm portions.Here, a surface that constitutes a U-shaped bottom portion, that is, abridge portion 482 is folded to become the rear side, and a right sidesurface 483 and a left side surface 484 are formed on the front sidefrom both right and left sides of the bridge portion 482 extending inthe vertical direction. The right side surface 483 and the left sidesurface 484 are formed to have bilateral plane symmetry, and the rightside surface 483 and the left side surface 484 constitute surfacesparallel to each other with a uniform gap. Right and left arm portions485 and 486 are formed on the front side from the front side of theupper portion of the right side surface 483 and the left side surface484, and proximal parts of the arm portions 485 and 486, that is, flatsurface portions 485 a and 486 a constitute parallel surfaces having theright-left direction at the same position as the right side surface 483and the left side surface 484. Crooked portions 485 b and 486 b bentinward are formed on the front side of the flat surface portions 485 aand 486 a. The crooked portions 485 b and 486 b have a flat surfaceshape. However, the large folded portion directed outward is disposedsuch that the ridgeline of its mountain becomes oblique.

Fitting portions 485 c and 486 c mountain-folded in a substantiallyV-shape are formed in front of the crooked portions 485 b and 486 a. Thefitting portions 485 c and 486 c are parts having a shape projectedtoward the inner side. In the part, when the battery pack 100 ismounted, summit parts on the inner side of the fitting portions 485 cand 486 c come into contact with and slide in plate-shaped apparatusside terminals. Therefore, even if they have a substantially V-shape,the peak parts (summit parts) thereof are configured to have the largeradius R1 of curvature or a small radius of curvature. This is becauseelectrical contact resistance is reduced by decreasing slide resistancebetween the apparatus side terminal and the fitting portions 485 c and486 c at the time of sliding and increasing the contact area withrespect to the fitting portions 485 c and 486 c at the time ofnon-sliding and being in contact. Guide portions 485 d and 486 d forguiding plate-shaped apparatus side terminals to be inserted between thefitting portions 485 c and 486 c are connected to the front side of thefitting portions 485 c and 486 c. The guide portions 485 d and 486 dhave a substantially flat surface shape and have a shape expanding inthe right-left direction as they go to the front side. Accordingly, tipportions 485 e and 486 e of the arm portions 485 and 486 have a shapepositioned below the arm portions 485 and 486. In the tip portions 485 eand 486 e, rounded corner portions are formed to depict a small radiusof curvature.

FIG. 30(2) is a view for describing a positional relationship betweenthe apparatus side terminal and the contact part in the fitting portions485 c and 486 c. Here, only a part of the arm portion 486 on the leftside is illustrated. However, the arm portion 485 on the right side hasplane symmetry only, and the shape is similar thereto. A width W of thearm portion 486 in the height direction is uniform along the front-reardirection. However, the contact part of the fitting portion 486 cbecomes a position indicated by the bold line. The contact partindicated by this bold line constitutes a linear contact portion or acontact region having a narrow width and a rectangular shape. Regardingthe contact part indicated by the bold line, the contact length becomesW/cos θ times with respect to the length (=W) when the fitting portion486 c is formed on a vertical line. In this manner, disposition isperformed such that the longitudinal direction of the contact portion orthe contact region of the fitting portion 486 c becomes oblique withrespect to the mounting direction of the apparatus side terminal on thecontact surface with respect to the apparatus side terminal. Therefore,the contact portion or the contact region can be increased, and thecontact area with respect to the apparatus side terminal on the powertool main body side can be expanded. As a result, the contact resistancebetween the apparatus side terminal and the fitting portion 486 c can bereduced, and heat generation of the terminals caused by increase incontact resistance can be effectively suppressed. In addition, sincegeneration of an are between the fitting portion 486 c and the apparatusside terminal can be suppressed, the arm portions 485 and 486 can beprevented from being damaged or fusion-cut. Regarding the upper positiveelectrode terminals 461 and 462 and the lower positive electrodeterminals 471 and 472 constituting the power terminals, similar to thefirst example, the positive electrode terminals of the upper cell unit146 and the lower cell unit 147 may be connected to each other, suchthat it is applied to a battery pack that can be switched between a lowvoltage side and a high voltage side similar to the first example. Insuch a case, in the fitting portions of the upper terminal component 200(refer to FIG. 5) and the lower terminal component 220 (refer to FIG. 5)described in the first example, the shapes of the arm portions and thefitting portions in the third example may be applied.

Regarding the terminals (upper terminal components 464 to 466 and 468and lower terminal components 474 to 476 and 478 in FIG. 28(2)) fortransmitting a signal as well, fitting portions are formed in two stageson the upper and the lower side, and these are configured to have thesame potentials such that the same signal flows. However, the upper andlower parts of the signal terminals may be configured to increase thenumber of transmitting signals by forming the parts to have differentpotentials and causing the apparatus side terminal on the power toolmain body side to be similarly formed in a separated manner. Inaddition, regarding the terminals for transmitting a signal, since it isless necessary to use terminal components that are completely separatedin a vertical direction, the terminals may be formed as terminalcomponents that are vertically coupled to each other. Next, a shape of avertically coupled terminal component 500 will be described withreference to FIG. 31.

FIG. 31 is a perspective view illustrating a shape of the terminalcomponent 500. However, illustration of the leg portions of the terminalcomponent 500 is omitted, and only a part positioned on the upper sideof the circuit board 450 is illustrated. In the terminal component 500,an arm portion piece 506 on the upper side and an arm portion piece 510on the lower side are formed in an approximately half part on the frontside of an arm portion 505 on the right side by forming a cutout groove508 vertically dividing the arm portion 505. Similarly, an arm portionpiece 507 on the upper side and an arm portion piece 511 on the lowerside are formed in an approximately half part on the front side of anarm portion 506 on the left side by forming a cutout groove 512vertically dividing the arm portion 506. In this manner, the terminalcomponent 500 is divided into the arm portion pieces 506 and 507 on theupper side and the arm portion pieces 510 and 511 on the lower side bythe cutout grooves 508 and 512. Therefore, in one terminal component500, a configuration of having two sets of arm portions can be realized,so that it is possible to realize a signal terminal that can retain afavorable fitting state. Fitting portions (506 c and 507 c) and fittingportions (510 c and 511 c) to be fitted into a plate-shaped main bodyside connection terminal are respectively formed in the terminal set(506 and 507) on the upper side and the terminal set (510 and 511) onthe lower side (here, the fitting portions 506 c and 510 c are not shownin FIG. 31). In the fitting portions (506 c and 507 c) on the upperside, the longitudinal direction of the contact portion or the contactregion is obliquely disposed. In a similar manner, in the fittingportions (510 c and 511 c) on the lower side, the longitudinal directionof the contact portion or the contact region is obliquely disposed. Thelongitudinal directions of the contact portion or the contact region ofthe fitting portions on the upper side and the lower side are disposedto be arranged in a row. The fitting portions on the upper side and thelower side are disposed to be at the same positions when viewed in thefront-rear direction. The longitudinal directions of the contact portionor the contact region of the fitting portions on the upper side and thelower side may be disposed not to be arranged in a row. In addition, thedirections of inclinations in the longitudinal directions of the fittingportions on the upper side and the lower side may be the oppositedirections without being aligned. For example, the shape of the armportion set (506 and 507) on the upper side may be changed to realize ashape that is obtained by vertically inverting the terminal set (510 and511) on the lower side, that is, the shape having plane symmetry withrespect to the horizontal surface. As described above, when thelongitudinal direction of the contact region of the fitting portion isformed in an oblique direction instead of the vertical direction,compared to an example in the related art in which the fitting portionis orthogonal to the mounting direction, the length of the fittingportion can be increased. Therefore, contact resistance can be reduced.

Hereinabove, in the third example, the shapes of the connectionterminals (480 and 500) used in a voltage-fixed battery pack have beendescribed. However, the shapes of these terminals may be configured tobe applied to a voltage switchable battery pack as in the first example.For example, the signal terminal component 240 illustrated in FIG. 9 mayemploy the way of disposing the fitting portions of the terminalcomponent 500 illustrated in FIG. 31.

Hereinabove, the present disclosure has been described based on theexamples. However, the present disclosure is not limited to the examplesdescribed above, and various changes can be made within a range notdeparting from the gist thereof. For example, in the example describedabove, an 18 V/36 V voltage switchable battery pack has been described.However, the switchable voltage ratio is not limited thereto only, andother voltage ratios that can be switched by a combination ofseries-connection and parallel-connection may be adopted.

REFERENCE SIGNS LIST

-   -   1, 1A Power tool main body    -   2 Housing    -   3 Handle portion    -   4 Trigger switch (operation switch)    -   5 Motor    -   10 Battery pack mounting portion    -   11 a Rail groove    -   12 Curved portion    -   14 Projection portion    -   15 Battery pack    -   20 Terminal portion    -   20 a Vertical surface    -   20 b Horizontal surface    -   21 Base    -   22 Positive electrode input terminal    -   22 a Terminal portion    -   27 Negative electrode input terminal    -   28 LD terminal    -   30 Power tool main body    -   30A Power tool main body    -   30B Power tool main body    -   32 Housing    -   33 Handle portion    -   34 Operation switch    -   35 Motor    -   40 Battery pack mounting portion    -   45 Motor    -   50 Terminal portion    -   51 Base    -   52 Positive electrode input terminal    -   52 a Terminal portion    -   52 b Coupling portion    -   52 c Wiring portion    -   53 Input/output port group    -   53 a Gap    -   53 b Gap    -   54 Connection terminal    -   54 a Terminal portion    -   54 b Connection portion    -   54 c Wiring portion    -   57 Negative electrode input terminal    -   57 a Terminal portion    -   57 b Coupling portion    -   57 c Wiring portion    -   58 LD terminal    -   59 Short bar    -   59 a Connection portion    -   59 b, 59 c Terminal portion    -   60 Controller    -   61 Power source circuit    -   62 Battery voltage detection circuit    -   63 Switch state detection circuit    -   64 Current detection circuit    -   65 Input line    -   72A, 72B Positive electrode terminal    -   72 d Cutout    -   79 Short bar    -   79 b Terminal portion    -   79 d Cutout    -   82 Positive electrode input terminal    -   82 a Terminal portion    -   82 b Connection portion    -   82 c Wiring terminal portion    -   87 Negative electrode input terminal    -   87 a Terminal portion    -   87 c Wiring terminal portion    -   89 Short bar    -   89 a Connection portion    -   89 b, 89 c Terminal portion    -   100, 100A Battery pack    -   101 Lower casing    -   101 a Front surface wall    -   101 b Rear surface wall    -   101 c Right side wall    -   101 d Left side wall    -   103 a, 103 b Screw hole    -   104 Slit (vent-hole)    -   110 Upper casing    -   111 Lower stage surface    -   113 Opening portion    -   114 Stepped portion    -   115 Upper stage surface    -   115 a Protrusion portion    -   120 Slot group disposition region    -   121 to 128 Slot    -   131 Stopper portion    -   132 Raised portion    -   134 Slit (vent-hole)    -   138 a, 138 b Rail    -   141 Latch    -   142 a Engagement portion    -   142 b Engagement portion    -   145 Separator    -   146 Upper cell unit    -   147 Lower cell unit    -   147 a Battery cell    -   148 Cell unit    -   149 Upper cell unit    -   150 Circuit board    -   150 a Front surface side    -   150 b Rear surface side    -   151 Attachment hole    -   153 a, 153 b Land    -   155, 155 a Adhesive resin    -   156 a Main region (for injecting resin)    -   156 b Sub-region (for injecting resin)    -   157 to 159 Wiring pattern    -   161, 162 Upper positive electrode terminal    -   162 a, 162 b Arm portion    -   164 T terminal    -   165 V terminal    -   166 LS terminal    -   167 Upper negative electrode terminal    -   167 a, 167 b Arm portion    -   168 LD terminal    -   171 Lower positive electrode terminal    -   172 Lower positive electrode terminal    -   172 a Arm portion    -   177 Lower negative electrode terminal    -   177 a, 177 b Arm portion    -   180 Board cover    -   181 Coupling portion    -   181 a Upper surface    -   181 b Front wall surface    -   181 c Cutout portion    -   182 Partitioning wall    -   182 a Vertical wall portion    -   182 b Horizontal wall portion    -   182 c Left end position    -   183 Partitioning wall    -   183 a Vertical wall portion    -   183 b, 183 c Horizontal wall portion    -   184 Partitioning wall    -   184 a, 184 d Vertical wall portion    -   184 b Horizontal wall portion    -   184 c Closing plate    -   185 Partitioning wall    -   187 Partitioning wall    -   187 a Vertical wall portion    -   187 b Horizontal wall portion    -   188 Partitioning wall    -   188 a Vertical wall portion    -   188 b Horizontal wall portion    -   190 Switch    -   191 Prism    -   200, 200A Upper terminal component    -   201 Base body portion    -   202 Bridge portion    -   203 Right side surface    -   204 Left side surface    -   203 a, 204 a Bent portion    -   203 b, 204 b Protrusion portion    -   203 c, 204 c Cutout portion    -   205, 206 Arm portion    -   205 a, 206 a Flat surface portion    -   205 b, 206 b Crooked portion    -   205 c, 206 c Flat surface portion    -   205 d, 206 d Fitting portion    -   205 e, 206 e Guide portion    -   205 f, 206 f Cutout portion    -   207, 208 Leg portion    -   207 a, 208 a Cutout portion    -   209 Gap    -   211 Gap    -   220, 220A Lower terminal component    -   221 Base body portion    -   222 Bridge portion    -   223 Right side surface    -   223 a Bent portion    -   223 c Cutout portion    -   224 Left side surface    -   225, 225A, 226 Arm portion    -   225 a, 226 a Flat surface portion    -   225 b, 226 b Crooked portion    -   225 c, 226 c Flat surface portion    -   225 d, 226 d Fitting portion    -   225 e, 226 e Guide portion    -   225 f, 226 f Cutout portion    -   227, 228 Leg portion    -   227 a, 228 a Cutout portion    -   231 Cutout portion    -   240 Signal terminal component    -   241 Base body portion    -   242 Bridge portion    -   243 Right side surface    -   243 a Extension portion    -   243 b Bent portion    -   243 c Cutout portion    -   244 Left side surface    -   245, 246 Arm portion base portion    -   249, 250 Leg portion    -   249 a Cutout portion    -   250 a, 250 b Stepped portion    -   251 to 254 Arm portion    -   256 Solder    -   260 Upper terminal component    -   262 Bridge portion    -   263 Right side surface    -   263 a Bent portion    -   264 Left side surface    -   264 b Dotted line    -   264 c Reinforcement surface    -   265, 266 Arm portion    -   265 d Fitting portion    -   267 and 268 Leg portion    -   280, 280A Lower terminal component    -   282 Bridge portion    -   283 Right side surface    -   284 Left side surface    -   284 b Dotted line    -   284 c Cut-off portion    -   285, 286 Arm portion    -   285 d Fitting portion    -   291 Cutout portion    -   300 Protective IC    -   301 Start-up terminal    -   302 Operation signal    -   305 Over-discharge signal    -   306 Overcharge signal    -   310 Current consumption control means    -   320 Protective IC    -   321 Power source circuit    -   322, 322A Upper voltage detection circuit    -   325 Over-discharge signal    -   326 Overcharge signal    -   327 Current detection circuit    -   328 LD terminal voltage detection circuit    -   329 Shunt resistor    -   331 Cell temperature detection means    -   335 Residual quantity display means    -   341 Discharging prohibition signal    -   342 Connection line    -   350 Controller    -   351 Microcomputer    -   352 Input port group    -   353 Input/output port group    -   364 Switching means    -   400 Battery pack    -   401 Lower casing    -   411 Lower stage surface    -   415 Upper stage surface    -   420 Slot    -   432 Raised portion    -   441 Latch    -   446 Battery cell    -   450 Circuit board    -   461, 462 Upper positive electrode terminal    -   464 T terminal    -   465 V terminal    -   466 LS terminal    -   467 Upper negative electrode terminal    -   468 LD terminal    -   471, 472 Lower positive electrode terminal    -   474 T terminal    -   475 V terminal    -   476 LS terminal    -   477 Lower negative electrode terminal    -   478 LD terminal    -   480 Upper terminal component    -   482 Bridge portion    -   483 Right side surface    -   484 Left side surface    -   485 Arm portion    -   485 a Flat surface portion    -   485 b Crooked portion    -   485 c Fitting portion    -   485 d Guide portion    -   485 e Tip portion    -   486 Arm portion    -   486 c Fitting portion    -   500 Terminal component    -   505 Arm portion    -   506 and 507 Arm portion piece    -   508 Cutout groove    -   509 Arm portion    -   510 and 511 Arm portion piece    -   512 Cutout groove    -   AN1 Input port    -   IO0 to IO0 Input/output port    -   LD0 to LD3 Light emitting diode    -   TH1 to TH3 Thermistor    -   Imax Current limit value (during discharge)    -   Tmax Upper limit value    -   VCC1 Power source voltage    -   VDD1 Power source voltage (of microcomputer)    -   VDD2 Reference voltage (of protection IC)    -   Vmax Cell voltage upper limit value    -   Vmin Cell voltage lower limit value

1. A battery pack comprising: a plurality of cell units in which aplurality of battery cells are connected in series, wherein the cellunits are switchable between an output of series-connection and anoutput of parallel-connection, wherein a protection circuit thatmonitors a state of the battery cells is provided for every cell unit,and wherein a microcomputer to which signals of the plurality ofprotection circuits are input is connected to the protection circuitthat is provided in the cell unit of the plurality of cell units in alowermost stage connected to a ground side at a time ofseries-connection.
 2. The battery pack according to claim 1, wherein apower source circuit that generates a power for driving themicrocomputer is provided, and the power source circuit generates thepower from an output of the cell unit in the lowermost stage thatbecomes close to the ground side at the time of series-connection. 3.The battery pack according to claim 1, wherein an adjustment circuit forbalancing a total power consumption of the protection circuit includingthe microcomputer in the cell unit in the lowermost stage and a powerconsumption of the protection circuits in the cell units other than thecell unit in the lowermost stage is provided on a side of the cell unitsother than the cell unit in the lowermost stage.
 4. The battery packaccording to claim 1, wherein a condition for an overload protection ischanged depending on whether the plurality of cell units are connectedin series or connected in parallel.
 5. The battery pack according toclaim 1, wherein a condition for an overload protection is changeddepending on whether a main body side microcomputer is included or themain body side microcomputer is not included on an electric apparatusmain body side on which the battery pack is mounted.
 6. A battery packcomprising: at least first cell unit and second cell unit as cell unitsin which a plurality of battery cells are connected in series, whereinthe cell units are configured to be switched between a series-connectionstate and a connection state other than the series-connection state, inthe series-connection state the first cell unit and the second cell unitare connected to each other in series while the first cell unit isconnected to a higher voltage side than the second cell unit, whereinthe battery pack includes a controller that is directly or indirectlyconnected to the first cell unit and the second cell unit and isconfigured to monitor a state of the battery cells constituting thefirst cell unit and a state of the battery cells constituting the secondcell unit and to be able to output a control signal for controlling adischarging of the battery pack, a power source circuit that isconnected to the controller and is configured to be able to supply apower source voltage to the controller, and a casing that accommodatesthe first cell unit, the second cell unit, the controller, and the powersource circuit and is configured to be able to connect the battery packto an electric apparatus main body, and wherein the power source circuitis configured to be connected to one cell unit of the first cell unitand the second cell unit, the controller is configured to be connectedto the power source circuit and a negative electrode of the one cellunit, and the power source circuit is configured to generate the powersource voltage from a voltage input from the one cell unit and to supplythe power source voltage to the controller.
 7. The battery packaccording to claim 6, wherein the power source circuit is configured tobe connected to the second cell unit as the one cell unit such that thepower source voltage is supplied from the second cell unit to thecontroller via the power source circuit.
 8. The battery pack accordingto claim 6, wherein the battery pack has a detection unit that isconnected to the controller, and the detection unit is configured todetect a physical quantity related to the battery pack or the electricapparatus main body connected to the battery pack and to output aninformation of the physical quantity to the controller.
 9. The batterypack according to claim 8, wherein the battery pack has a first voltagedetection unit as the detection unit connecting an other cell unit ofthe first cell unit and second cell unit and the controller to eachother, and the first voltage detection unit is configured to output aninformation of a voltage of the other cell unit to the controller as thephysical quantity.
 10. The battery pack according to claim 6, whereinthe controller is configured to control a discharging or a charging ofthe battery pack in accordance with the connection state of the cellunits.
 11. The battery pack according to claim 8, wherein the batterypack has a second voltage detection unit as the detection unitconfigured to be able to be connected to a terminal of the electricapparatus main body, and the second voltage detection unit is configuredto output an information of a voltage input from the terminal of theelectric apparatus main body to the controller as the physical quantity.12. The battery pack according to claim 6, wherein the controller isconfigured to control a discharging or a charging of the battery pack inaccordance with a kind of the electric apparatus main body connected tothe battery pack.
 13. An electric apparatus comprising: the battery packaccording to claim 1; and at least a first electric apparatus main bodyas an electric apparatus main body that is able to be connected to thebattery pack, wherein when the battery pack is connected to the firstelectric apparatus main body, the battery pack is in a series-connectionstate in which the cell units are connected to each other in series, andwherein when the battery pack is not connected to the first electricapparatus main body, the battery pack is in a non-connection state inwhich the first cell unit and second cell unit are electricallyindependent from each other.
 14. An electric apparatus comprising: thebattery pack according to claim 1; and at least a second electricapparatus main body as an electric apparatus main body that is able tobe connected to the battery pack, wherein when the battery pack isconnected to the second electric apparatus main body, the battery packis in a parallel-connection state in which the cell units are connectedto each other in parallel, and wherein when the battery pack is notconnected to the second electric apparatus main body, the battery packis in a non-connection state in which the first cell unit and secondcell unit are electrically independent from each other.
 15. An electricapparatus comprising: the battery pack according to claim 6; and atleast a first electric apparatus main body as an electric apparatus mainbody that is able to be connected to the battery pack, wherein when thebattery pack is connected to the first electric apparatus main body, thebattery pack is in a series-connection state in which the cell units areconnected to each other in series, and wherein when the battery pack isnot connected to the first electric apparatus main body, the batterypack is in a non-connection state in which the first cell unit andsecond cell unit are electrically independent from each other.
 16. Anelectric apparatus comprising: the battery pack according to claim 6;and at least a second electric apparatus main body as an electricapparatus main body that is able to be connected to the battery pack,wherein when the battery pack is connected to the second electricapparatus main body, the battery pack is in a parallel-connection statein which the cell units are connected to each other in parallel, andwherein when the battery pack is not connected to the second electricapparatus main body, the battery pack is in a non-connection state inwhich the first cell unit and second cell unit are electricallyindependent from each other.